Microeconomics I and Statistics As Per New B Com CBCS Syllabus 2017 for CU REVISED SECOND EDITION Press

Microeconomics I and Statistics As per new B Com CBCS syllabus 2017 for CU REVISED SECOND EDITION Press

Panchanan Das Professor, Department of Economics University of Calcutta University Anindita Sengupta Associate Professor, Department of Economics Hooghly Women’s College OxfordUniversity of Burdwan

Microeconomics.indb 1 6/21/2017 6:43:19 PM 3

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Economics_FM.indd 2 6/22/2017 1:52:55 PM Preface

This text onMicroeconomics I and Statistics is strictly for Paper GE 1.1 Chg. of Semester I which is common to honours and general courses in the new syllabus prescribed by the University of Calcutta under the framework of choice based credit system (CBCS) of the University Grants Commission (UGC). The book is designed to cover all the topics keeping in mind the structure of CBCS provided in the UGC guidelines of CBCS. As the total credit hours for each paper under the new system are strictly specified, the chapters in the book are precise, yet comprehensive and easy-to-understand for honours and general undergraduate students of commerce under the University of Calcutta. While it contains the necessary topics completely covering the syllabus of the University of Calcutta, it also captures well the syllabi prescribed by the leading universities in India.

About the Book Microeconomics I and Statistics is designed for undergraduate commercePress students and others in learning microeconomic theory and basic statistics. The main purpose is to articulate the basic questions of microeconomic theory and statistical problems in a student-friendly manner. The primary objective is to motivate the students to learn the concepts, to conceptualize the problem properly, and to secure good marks in the University examination. Some problems on microeconomics are discussed with mathematical treatment along with graphical illustration to understand the problem clearly and more logically. The mathematical parts are for advanced learning, especially for curious students, while others could skip these parts without losing the logic of the problem. University Key Features • The contents of the book and sequence of topics are prepared by following the CBCS-based new syllabus prescribed by the University of Calcutta. • Practical examples are inserted to make theories easily understandable to the students. • Numerical problems areOxford provided to understand different aspects of microeconomics and statistics. • A plethora of numerical examples, and exercises including multiple-choice questions with answers are provided by following the probable question patterns in the semester system. • Solutions of the University questions as well as model questions are provided, which will help the students to prepare for their examinations.

Organization of the Book The first part containing microeconomic theory is divided into five chapters by following the sequence as shown in Module I of the syllabus. Chapter 1 provides a basic idea of the demand function and the related issues on law of demand. The law of demand is explained and illustrated in terms of charts and diagrams. The perceptions of elasticities of demand have been discussed clearly. Ideas about the elasticities of demand are necessary to conceptualize

Microeconomics.indb 4 6/21/2017 6:43:20 PM Preface v

the nature of demand for different commodities. This chapter takes care of different concepts of elasticities of demand in a comprehensive manner. Chapter 2 focuses on the problems of consumers’ behaviour under the framework of Marshallian cardinal utility approach, and ordinal utility approach developed first by Hicks and Allen. In a market-based economy, consumers determine the demand for goods and services, and the supply of inputs used in production by solving the constrained utility maximization problem. The concepts of price effect, substitution effect, and income effect are illustrated graphically to easily understand the different shapes of the demand curve for a commodity. Chapter 3 discusses the concepts of production function, both under short run and long run. Production is an economic activity performed by the firms. Firms determine the supply of output and demand for inputs by solving either constrained output maximization, or constrained cost minimization, or ultimately, profit maximization problem. The problems of constrained optimization that a rational firm has to face is analysed in this chapter with the help of isoquants and isocost lines. The notion of homogeneous function is highly mathematical. However, we have used this concept in a simple form to analyse the behaviour of the long-run production function. Chapter 4 contains different ideas about costs of production mostly relevant in business economics. Cost functions are basically the mirror image of production functions. PressThe derivation of different aspects of cost function from the production function has been illustrated intelligibly by using simple functional form as well as graphical techniques. Chapter 5 deals with the market analysis. Exchange between consumers and firms—the two basic economic agents—takes place in the market to determine equilibrium quantity and price of a commodity. Microeconomics deals with the market for a particular commodity. This chapter deals with the nature and characteristics of a perfectly competitive market. Walrasian and Marshallian stability in a competitive market are illustrated lucidly. The impacts of taxes and subsidy in the framework of demand and supply are also discussed in this chapter. University The second part of this book deals with statistics based on Module II of the syllabus prescribed by the University of Calcutta. All chapters in this module contain sufficient numerical examples and many numerical problems for self-assessment of the students. Chapter 1 of the second part of this book discusses some fundamentals in statistics. It covers the basic steps to be followed in theOxford collection of data and their proper presentation in tabular form, graphs, and figures. Summarization of data is an important step for statistical analysis. Frequency distribution is a popular form of summarization of data. This chapter illustrates the different aspects of frequency distribution and its diagrammatic presentation. Chapter 2 covers the measures of central tendency and discusses how to calculate them, and under what conditions a particular measure may be used most appropriately. The mean, median, and mode are the popular measures of central tendency. This chapter deals with these measures of central tendency of a distribution. Chapter 3 deals with the measures of dispersion that seek to quantify the variability of the data. This chapter is concerned with some important measures of dispersion such as range, quartile deviation, mean deviation, and standard deviation, to quantify the extent to which the values in a distribution differ from the average of the distribution. Chapter 4 takes care of various statistical techniques to distinguish among the various shapes of a distribution. This chapter makes the student familiar with some statistical measures in terms of moments, the concept of skewness and kurtosis.

Microeconomics.indb 5 6/21/2017 6:43:20 PM vi Preface

Chapter 5 contains different methods of interpolation used in statistics and mathematics. Interpolation, is not only useful in statistics, but is also useful in science, business, or any time there is a need to predict values that fall within two existing data points.

Acknowledgements It is a great pleasure to thank those people who have helped us put this book together. Their generosity and insights were generous. We, of course, are solely responsible for any errors. We acknowledge our debts especially to our colleagues and friends at the University of Calcutta, Goenka College of Commerce and Business Administration, and Hooghly Women’s College, many of whom have been of immense help while preparing this text. We like to thank the Head of the Department of Economics of the University of Calcutta, and the Principal of Hooghly Women’s College who inspired us at different stages of the project. Comments given at the early stage by several colleagues after going through large portions of the manuscript very much improved the book. We are grateful to all that we have discovered while teaching our students. We hope this book can serve to help them. Comments made by the reviewers are gratefully acknowledged.Press We also thank the editorial team at Oxford University Press, India for all their patience and support. Panchanan Das Anindita Sengupta

University

Oxford

Microeconomics.indb 6 6/21/2017 6:43:20 PM Brief Contents

Preface iv Detailed Contents viii Features of the Book xii Road Map xiv

PART I MICROECONOMICS I 1 1. Basics of Demand 3 2. Theory of Consumer Behaviour 27 3. Theory of Production 58 4. Theory of Cost Press 92 5. Perfect Competition 113

Question Bank 135 Solved CU Question Papers—2014–2016 140 Model Question Papers 166

PARTUniversity II STATISTICS 171 1. Fundamentals 173 2. Measures of Central Tendency 210 3. Measures of Dispersion 239 4. Moments, Skewness, andOxford Kurtosis 257 5. Interpolation 271

Question Bank 286 Solved CU Question Papers—2014–2016 294 Model Question Papers 323 About the Authors 330 Additional Multiple Choice Questions A-1

Microeconomics.indb 7 6/21/2017 6:43:20 PM Detailed Contents

Preface iv Brief Contents vii Features of the Book xii Road Map xiv

PART I MICROECONOMICS I 1 1. Basics of Demand 3 1.5.6 Income Elasticity of 1.1 Introduction 3 Demand 19 1.2 Demand Function 3 1.5.7 Measurement of Income Elasticity 1.3 The Law of Demand 5 of Demand 20 1.3.1 Demand Schedule 6 2. Theory of Consumer Behaviour 27 1.3.2 Derivation of Individual 2.1 IntroductionPress 27 Demand Curve 6 2.2 Marshallian Utility Theory 28 1.3.3 Derivation of Market Demand 2.2.1 Basic Assumptions of Cardinal Curve 6 Utility Theory 28 1.3.4 Movement along the Demand 2.2.2 Equilibrium of the Consumer in Curve 7 the Cardinal Utility Theory 30 1.3.5 Shifting of the Demand 2.2.3 Derivation of the Demand Curve 8 Curve from the Cardinal Utility 1.4 Exceptions to the Law of Demand 9 Theory 33 1.4.1 Giffen Goods 9 University 2.2.4 Consumer’s Surplus in the 1.4.2 Conspicuous Consumption 9 Cardinal Utility Theory 34 1.4.3 Conspicuous Necessities 10 2.2.5 Limitations of Cardinal Utility 1.4.4 Ignorance 10 Theory 35 1.4.5 Emergencies 10 2.3 Ordinal Utility Theory or Indifference 1.4.6 Future Changes in Prices 11 Oxford Curve Theory 36 1.4.7 Change in Fashion 11 2.3.1 Axioms of Choice in the Ordinal 1.5 Elasticity of Demand 11 Utility Theory 36 1.5.1 Own Price Elasticity of 2.3.2 Indifference Curve and Demand 11 Indifference Map 38 1.5.2 Measurement of Own Price 2.3.3 Properties of Indifference Elasticity of Demand 12 Curve 39 1.5.3 Elastic and Inelastic 2.4 Budget Line 43 Demand 15 2.5 Consumer’s Equilibrium 44 1.5.4 Distinction between Slope of a 2.6 Income–Consumption Curve 46 Demand Curve and Elasticity of 2.7 Price–Consumption Curve 48 Demand 16 2.7.1 Derivation of Demand Curve 1.5.5 Cross-price Elasticity of from Price–Consumption Demand 18 Curve 48

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2.8 Hicksian Decomposition of Price 3.18 Homogeneous Production Function Effect into Substitution Effect and and Returns to Scale 87 Income Effect 49 4. Theory of Cost 92 2.8.1 Substitution Effect and 4.1 Introduction 92 Income Effect for Normal, 4.2 Accounting Cost and Economic Inferior, and Giffen Goods 50 Cost 93 2.9 Demand Curve for Normal, Inferior, 4.3 Private Cost and Social Cost 94 and Giffen Goods 51 4.4 Fixed Cost and Variable Cost 94 2.10 Indifference Curve Theory is Better 4.5 Short-run Cost and Long-run Cost 97 than Marshallian Cardinal 4.6 Short-run Total Cost Curve, Utility Theory—Reasons 52 Short-run Total Fixed Cost Curve, 3. Theory of Production 58 and Short-run Total Variable 3.1 Introduction 58 Cost Curve 98 3.2 Concept of Production 58 4.7 Short-run Average Cost Curve, 3.3 Factors of Production 59 Short-run Average Fixed Cost 3.4 Production Function 59 Curve, and Short-run Average 3.5 Total Product, Average Product, VariablePress Cost Curve 99 and Marginal Product 60 4.7.1 Derivation of Short-run 3.6 Short-run Production: Laws of Average Fixed Cost Curve 99 Variable Proportions 61 4.7.2 Derivation of Short-run 3.7 Relation between Total Product Average Variable Cost and Average Product 63 Curve 100 3.8 Relation between Total Product 4.7.3 Derivation of Short-run Average and Marginal Product 64 Cost Curve 101 3.9 Relation between Average University 4.8 Marginal Cost 102 Product and Marginal Product 65 4.8.1 Short-run Marginal Cost 3.10 Stages of Production 66 Curve 102 3.11 Short-run Equilibrium of a Firm 67 4.8.2. Relation between Short-run 3.12 Long-run Production 68 Average Cost and Short-run 3.12.1 Isoquant 68 Marginal Cost 103 3.12.2 Slope of anOxford Isoquant: 4.9 Long-run Total Cost Curve 104 Marginal Rate of Technical 4.11 Long-run Average Cost Curve 106 Substitution 69 4.11 Long-run Marginal Cost Curve 109 3.12.3 Properties of Isoquant 71 5. Perfect Competition 113 3.13 Ridge Lines and Economic Region 5.1 Introduction 113 of Production 74 5.2 Meaning of Market in Economics 113 3.14 Isocost Line 75 5.3 Features of Perfectly Competitive 3.15 Optimal Input Combination 78 Market 115 3.15.1 Output Maximization 5.4 Concept of Revenue 116 Subject to Cost Constraint 78 5.5 Short-run Equilibrium of the Firm 3.15.2 Cost Minimization Subject to in a Perfectly Competitive Market 118 Output Constraint 81 5.6 Short-run Supply Curve of the 3.16 Expansion Path 83 Firm and the Industry 121 3.17 Returns to Scale 85

Microeconomics.indb 9 6/21/2017 6:43:20 PM x Detailed Contents

5.7 Long-run Equilibrium of the Firm 5.9 Stability Analysis—Walrasian and and the Industry 124 Marshallian 127 5.8 Producer Surplus under Perfect 5.10 Demand–Supply Analysis: Impact Competition 126 of Taxes and Subsidy 130

Question Bank 135 Solved CU Question Papers—2014–2016 135 Model Question Papers 161

PART II STATISTICS 171 1. Fundamentals 173 1.9.3 Cumulative Frequency Graph 1.1 Definition of Statistics 173 or Ogive 204 1.1.1 Definitions by A.L. Bowley 173 2. Measures of Central Tendency 210 1.1.2 Definition by Croxton and 2.1 Introduction 210 Cowden 174 2.2 Mean 210 1.1.3 Definition by Horace 2.2.1Press Arithmetic Mean 211 Secrist 174 2.2.2 Geometric Mean 218 1.2 Scope of Statistics 175 2.2.3 Harmonic Mean 222 1.3 Limitations of Statistics 176 2.3 Median 224 1.4 Variable and Attribute 178 2.3.1 Calculation of Median by 1.5 Primary and Secondary Data 178 Graphical Method 227 1.5.1 Methods of Primary Data 2.3.2 Properties of Median 229 Collection 179 2.4 Other Measures of Location 229 1.5.2 Methods of Secondary Data 2.5 Mode 229 Collection 183 University 2.5.1 Calculation of Mode in Grouped 1.6 Tabulation of Data 184 Frequency Distribution 230 1.7 Graphs and Charts 186 2.5.2 Calculation of Mode by 1.7.1 Types of Graphs and Graphical Method 231 Charts 186 2.5.3 Mode as a Measure of 1.8 Frequency Distribution 192 Oxford Central Tendency 232 1.8.1 Simple Frequency 2.6 Essential Features of a Good Distribution 193 Measure of Location 232 1.8.2 Grouped Frequency Distribution 193 3. Measures of Dispersion 239 1.8.3 Cumulative Frequency 3.1 Introduction 239 Distribution 198 3.2 Range 240 1.8.4 Relative Frequency 3.3 Quartile Deviation 240 Distribution 200 3.4 Mean Absolute Deviation 241 1.9 Diagrammatic Presentation of 3.4.1 Calculation of Mean Absolute Frequency Distribution 201 Deviation from Mean for 1.9.1 Histogram 201 Ungrouped Data 242 1.9.2 Frequency Polygon 202 3.4.2 Mean Absolute Deviation for Frequency Distribution 243

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3.4.3 Some Useful Results about 4.3.2 Measures of Skewness 263 Mean Deviation 245 4.3.3 Characteristic of a Good Measure 3.5 Standard Deviation 245 of Skewness 267 3.5.1 Properties of Standard 4.4 Kurtosis 267 Deviation 246 5. Interpolation 271 3.5.2 Calculation for Standard 5.1 Introduction 271 Deviation for Discrete and 5.2 Finite Differences— D and Continuous Series 248 E Operators 273 3.6 Relative Measures of Dispersion 250 5.2.1 Forward Difference 3.7 Comparison of Measures of Operator 273 Dispersion 252 5.2.2 Shift Operator 274 4. Moments, Skewness, and Kurtosis 257 5.2.3 Algebraic Rules of Operators 274 4.1 Introduction 257 5.3 Polynomial Function 275 4.2 Moments 257 5.4 Newton’s Forward Interpolation 4.2.1 Non-central Moments 257 Formula 278 4.2.2 Raw Moments 258 5.5 Newton’s Backward Interpolation 4.2.3 Central Moments 258 FormulaPress 280 4.3 Skewness 261 5.6 Lagrange’s Interpolation Formula 282 4.3.1 Nature of Skewness 262

Question Bank 286 Solved CU Question Papers—2014–2016 294 Model Question Papers 323 About the Authors 330 University Additional Multiple Choice Questions A-1

Oxford

Microeconomics.indb 11 6/21/2017 6:43:20 PM Fundamentals 167

Example 1.16 Consider the data given in Table 1.19 and draw a frequency polygon of it. Table 1.19

Class interval Frequency 6.5–8.5 4 8.5–10.5 5 10.5–12.5 17 12.5–14.5 36 14.5–16.5 27 16.5–18.5 11 18.5–20.5 5

Solution: First, we need the mid-point of the class interval. This is found as given in Table 1.20.

Table 1.20

Class interval Mid-point Frequency 6.5–8.5 7.5 4 8.5–10.5 9.5 5 10.5–12.5 11.5 17 12.5–14.5 13.5 36 Features of the Book14.5–16.5 15.5 27 16.5–18.5 17.5 11 18.5–20.5 19.5 5 Theory of Production 73

The frequency polygon obtained is shown as the curve in Fig. 1.8. Capital (K) B capital, it will have to use more labour as well to Uneconomic keep the total production constant.Frequency Consequently, Polygon region A 40 beyond point A0, isoquant Q0 will be positively C sloped.35 The firm will obviously not produce in this range,30 since the marginal productivity of capital Figures and Graphs A2 is negative and it is not profitable for the firm Economic Uneconomic to25 use capital anymore. Therefore, this range is region region Numerous well-labelled Q2 A1 the20 uneconomic range of production. Similarly, B2 figures and graphs are at15 point B0, use of labour reaches the maximum Q1 level. In other words, at point B0, the marginal A 0 B 10 provided throughout 1 productivity of labour is zero. Beyond point B0, Q0 the5 marginal productivity of labour becomes the book to graphically B0 negative0 and, therefore, if the firm wishes to use 65-8.5 8.5-10.5 10.5-12.5 12.5-14.5 14.5-16.5 16.5-18.5 18.5-20.5 present various O Labour (L) more labour, it will have to use more capital also to keep the total productionFig. 1.8 Frequencyconstant. Consequently,polygon economic theories. 2 Fig.Microeconomics 3.17 Ridge lines and 1 and economic Statistics and the beyond point B0, isoquant Q0 will be positively uneconomic regions of production sloped. The firm will obviously not produce in this range,2.2.1 since Arithmetic marginal productivityMean of labour is negative and it is not profitable for the firm to use labour anymore. Therefore, this range is also the uneconomic range of production. The arithmeticEconomics_Ch06.indd mean (AM), 167 or mean, of a variable is the sum of all the values in the data set of 13/06/17 2:55 PM Similarly, we get points such as A1 and B1 on isoquant Q1 and A2 and B2 on isoquant Q2, the variable divided by the number of units of that variable in the data set. Arithmetic mean is beyond which the isoquants become positively sloped.Press Locus of all points such as A0, A1, andof Atwo2Theory, that types: is, OAof unweighted ,Consumer is called the or Behaviourupper simple ridge arithmetic line 39where mean the marginal and weighted productivity arithmetic of capital mean. becomesUnweighted zero. On Arithmetic the other hand, Mean locus of all points such as B0, B1, and B2, that is, OB, is Table 2.5 Marginal ratecalled of the substitution lower ridge line, where the marginal productivity of labour becomes zero. Ridge lineThe is, thus,unweighted the locus ofarithmetic all such factor mean combinations is the simple where sum marginal of the productvalues of of aany set one of ofobservations of a Consumption of X Consumption of Y Total utilitythevariable twoderived factors divided becomes Marginal by the zero. ratenumber To of thesubstitution ofleft observations. of the upper ridge If we line have and n tovaluesTables the right of a ofvariable lower x as x1, x2, ..., ridgexn, the line, unweighted marginal productivity arithmetic(MRSxy = of dY/dX onemean )of theor, twosimple factors mean, becomes denoted negative by x and,, is: therefore, it is not profitable for the firm to produce in these regions. Hence, upperInformative ridge line and and n 1 12 U0 lower ridge line are the boundary– lines between the economic region and the uneconomic regions of production. ∑xi authoritative economic 2 8 U0 |(8 − 12)/(2xxx123+ − 1)| + = 4 ++... xn =1 If the firm continuesx = to move on higher isoquants,= i substitutability of twodata factors are decreases presented in(2.1) 3 5 U0 gradually. As a |(5result, − 8)/(3 the −convex 2)| = nn 3to the origin portion of the successively higher isoquants Example 2.1decreases. The Therefore, daily wages the (inupper `) ofand 10 lower workers ridge inlines a factory OA and areOB approachas follows:the one form240, another 275, of and numerous265, 270, 400, 4 3 U0 |(3 − 5)/(4 − 3)| = 2 Measures of Central Tendency 5 480, 670, ultimately850, 550, theyUniversity and intersect 250. at Calculate point C. Point the Cmean is known wage as the of Blissthe Point,workers. at which tables. the firm reaches 5 2 U0 the maximum possible|(2 − 3)/(5 level − of4)| output. = 1 Solution: Mean wage = `425 Proof: Let the variable x has n1 + n2 observations xi, i = 1, 2, …, n1 + n2, which is decomposed [Note: unit of measurement (in this example `) should be given in the answer] 3.14 Isocostinto Line 2 sets xj, j = 1, 2, … n1, and xk, k = 1, 2, …, n2. Therefore, we can write away less and less units of Y so that the marginal rate of substitution falls from 4 to 1 in the fifth Weighted Arithmeticnn12+ Mean n 1 n 2 combination. The aforementioned five combinationsThe cost ofX of andproduction Y are actuallyis extremely the= important points + A in, B conducting, C, production. Isocost line is the locus ofThe all such weighted factor input mean combinations ∑occursxxxi when ∑∑for which jkthere the are total several cost of productionobservations remains of the constant. same Invalue. To explain D, and E on the indifference curve IC0 as shown in Fig. 2.9. i=1 jk = 11 = Therefore, it is proved that as the consumerother weightedproceeds words, from meanan isocost upward consider line showsleft the tothe following downwarddifferent example: combinations right of factors of production that can be employed with a given total cost. Letnn12+ us take an example as shownn1 in Table 3.4. nSuppose2 that along the same indifference curve, the marginal rate of substitution diminishes. The diminishing Example 2.2a producer A restaurant has a totalOr, inbudget South()()nn12 +of `Kolkata120,∑ and xsoldfori/ producing nnmedium, 12 += a large,certain n 1 ∑∑ and xnnlevel jk // bigof 12 +output, size soft he/she xn drinks 2has for `35, `45, marginal rate of substitution betweenOxford andtwo `goods60, respectively. is the property Of theof a lastconvex 10 todrinks thei =origin 1sold, 3curve. were medium, jk= 114 were large, =and 3 were big. Find the Therefore, the indifference curve is convex to the origin. In case of a negatively sloped straight mean price of the last 10 drinksOr, () sold.n+=+ n x nx nx line, the marginal rate of substitution is constant and in case of a concave12 to the origin 1122 curve, Solution: The mean price of the lastnx 10 +drinks nx sold is the marginal rate of substitutionEconomics_Ch03.indd is increasing. 73 Or, x = 11 2 2 6/5/2017 12:33:01 PM 35+++++++++ 35 35 45 45+ 45 45 60 60 60 3 ×+×+× 35 4 45 3 60 Worked-out Examples x = nn12 = = 46.5 (`) Two Indifference Curves Can Never Touch or Intersect Each Other 343++ 343++ The composite mean lies between the group means, that is, x12≤≤ xx. To proveNumerous this property, worked- let us assume that twoIn indifference this example, curves the weights can touch are or frequency intersect counts.each other. Weighted arithmetic mean is related to a frequency Example 2.6 The average marks of 40 students in section A of B.Com Semester I is 65 and average In Fig. 2.10, two indifference curvesdistribution. IC0 and IC If 1the touch ith eachobservation other at of point a variable B. A and x isB arex and its frequency is f , then weighted arithmetic out examples are marks of 35 students in section B of the same semesteri is 68. Find the averagei marks of 75 students two points on the indifference curve meanIC0 and is B defined and C are as two points on the indifference curve provided in the section of both the section of B.Com Semester I. n IC1. Therefore, consumer is indifferent betweenA and B and also between B and C. According ∑fxii to onthe Statisticsaxiom of transitivity, to help the consumerSolution: should be We indifferentfx are+ given fx +the fxbetween following ++ A fand information. x C. However, x = 112233 nn= i=1 (2.2) this is impossible, because point C has more of both the commoditiesfff++++ X and f Y than point N A. students grasp the 123Sectionn Number of students Average marks Commodity Y Commodity Y concepts. All possible values of a variableSection formA what is known40 sample mean65 which is called statistic. Population A 12 as population distributionSection and Bthe mean of 35this represents the68 universal set, while the sample is a distribution is the population mean. Population is set drawn from this universal set. Any measurable C 8 B a theoretical distribution andCombined its mean is a parameter75 characteristic ?of a population is called a parameter. C which is unknownA and we need to estimate it with The mean of a population is a parameter. The mean 5 a sampleHere, drawnn1 = 40, from n2 =this 35, population. n1 + n2 = 75,A sample x1 = 65, of and a sample, x2 = 68 or any other measure based on sample D is a part of the population and its mean is the data, is called a statistic. 3 nx+B nx 40 ×+× 65 35 68 Now, x = 11 22= = 66.4 E IC 2 nn12+ 75 1 IC 0 IC0 © Oxford UniversityCalculation ofPress. AM for AllFrequency rights Distribution reserved.

O Discrete series Let us consider the following frequency distribution of a variable x. Here, xi 1234 5 O Commodity X Commodity X and fi denote the value of the variable and the corresponding frequency for observation unit i. Microeconomics.indb 12 Economics_Ch02.indd 2 Fig. 2.10 Two indifference curves touching 6/21/201709-06-2017 16:23:10 6:43:21 PM Fig. 2.9 Convexity of indifference curve each other xi fi fi xi

x1 f1 f1x1

x2 f2 f2x2

x3 f3 f3x3

Economics_Ch02.indd 39 ...6/5/2017 12:27:34 PM ......

xn fn fnxn

n n Total f ∑ i ∑ fxii i=1 i=1

Economics_Ch02.indd 5 09-06-2017 16:23:18 Theory of Consumer Behaviour 53

as a result of income effect. However, unlike the case negatively sloped but steeper than that of a normal of inferior goods, income effect of a Giffen good is good. On the contrary, the demand curve for a Giffen stronger than the substitution effect; therefore, the good is positively sloped. resultant effect goes against the direction of the • Indifference curve theory is better than Marshallian substitution effect. In other words, as price falls, theory in the sense that the former can explain the demand for Giffen good decreases and vice versa. exceptions to the law of demand, that is, the cases of • While the demand curve for a normal good is negatively inferior and Giffen goods, whereas the latter cannot sloped, the demand curve for an inferior good is also do that.

EXERCISES

[According to CU syllabus of Economic-I paper for B Com Honours and General, third unit requires 10 lectures and 12 marks. Therefore, we have incorporated the short-answer type questions carrying two marks, medium-answer type questions carrying four marks, and broad-answer type questions carrying eight marks in the exercise.] SHORT-ANSWER TYPE QUESTIONS (2 MARKS) 1. What do you mean by marginal utility? 17. What is an indifference map? 2. What would be the value of marginal utility when total 18. What doTheory you mean of byConsumer a budget line? Behaviour 53 utility is maximum? [CU B Com (G), 2008] 19. What are the conditions required to achieve consumer’s 3. What are the consumer’s equilibrium conditions in equilibrium in indifference curve theory? as a result of income effect. However, unlike the case negatively sloped but steeper than that of a normal ofMarshallian inferior goods, theory? income effect of a Giffen good is good. On the contrary, the demand[CU curve B Com for a(G), Giffen 2013] 4. strongerWhat is net than utility? the substitution effect; therefore, the 20.good What is positively is a price–consumption sloped. curve? 5. resultantWhat do youeffect mean goes by the against law of diminishingthe direction marginal of the • Indifference curve theory is better[CU. than B Com Marshallian (G), 2010] substitutionutility? effect. In other words, as price falls, 21.theory What in isthe an senseincome–consumption that the former curve? can explain the 6. demandIf marginal for utility Giffen is goodhigher decreases than the price and of vice the versa. 22.exceptions What do to you the mean law ofby demand,price effect? that is, the cases of • Whilecommodity, the demand what will curve the for consumer a normal do? good is negatively 23.inferior What and do youGiffen mean goods, by substitution whereas theeffect? latter cannot 7. sloped,If marginal the utility demand is less curve than for the an price inferior of the good is also 24.do that.What do you mean by income effect? 54 commodity, Microeconomics what will the 1 consumer and Statistics do? 25. What is the relationship between price effect, 8. What is the cardinal measurement of utility? substitution effect, and income effect? 4. 9. WhatWhat are is theconsumer’s two basic surplus? conditions [CU required B Com for (G), 2009] 13. 26. What Are isall a inferiorbudget line?goods Explain called Giffen the shifts goods? of a budget line. 10. equilibriumState two limitations of the consumer of cardinal in cardinal utility utilitytheory.EXERCISES theory? 14. What is income–consumption curve?[CU What B Com would (G), be 2006] 5. 11. WhatDistinguish are the basic between limitations cardinal of utility Marshallian and ordinal cardinal utility. 27.the What shape is of the an difference income–consumption between ‘Giffen curve good’if one andof the [Accordingutility theory? to CU syllabus of Economic-I[CU Bpaper Com for (G), B Com 2013] Honours andtwo‘inferior General, goods isgood’? third inferior? unit requires 10 lectures[CU B and Com 12 (G), marks. 2008] 6. 12. Therefore, ExplainWhat arethe we the axiomshave basic incorporated of axioms choice of in thechoice? ordinal short-answer utility theory.type questions carrying 15. 28. 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The horizontalbundle demandof chocolates curve impliesof that sweets the elasticityutility rate of (b) a decrease in both demand and supply derived substitution 4 170 – of demand is (c) an increase in both demand and supply Economics_Ch02.indd 53 (a) zeroA 15 1 U0 – 6/5/2017(d) a 12:27:56decrease PM in demand combined with an increase 5 190 – B.Com Examination(b) infiniteB 201410 2 U0 – in supply (c) equalC to one 6 3 U 9.– If a decrease in the price of gasoline increases the Does Puja experience the law of diminishing marginal 0 (New Syllabus)(d) greater than zero but less than infinity demand for large cars, then utility from consuming chocolates? D 3 4 U0 – Economics-I Solved 3. EachRelevant point Question on the demand Paper curve reflects (a) gasoline and large cars are complements in How do you know? E 1 5 U0 – Fourth Paper [C-14G] (a) the highest price consumers areFull willing Marks-100 and able consumption. Oxfordto pay for that particular unit of a good. (b) large cars areSolved an inferior CU good. Question Module-I(b) the highest price sellers will accept for all units (c) gasoline is an inferior good. they are producing. (d) gasoline andPapers/Model large cars are substitutes in Group-A(c) the lowest-cost technology available to produce a consumption. Economics_Ch02.indd 54 6/5/2017 12:27:56 PM 1. Answer the following questions: good. 2 × 5 10. A utility functionQuestion that describes howPapers much of a basket (a) State any two characteristics of business economics.(d) all the wants of a given household. of goods is preferred to another is called Ans. Two important characteristics of business 4. economics A substitute are: is a good (a) an ordinalStudents utility function. can learn (i) Microeconomics: Business economics is micro(a) of economic higher quality in character. than Thisanother is so good. because it studies (b) a cardinal fromutility function. solved previous the problems of an individualModel business Questionunit.(b) It does that notcan studybe used the Paper-1in problems place of of another the entire good. economy. (c) a utility-maximizing function. (ii) Also uses macroeconomics: Although business economics is micro economic in nature, years’ University marco economics is also useful to business(c) economics. that is not Macroeconomics used in place of provides another an good. intelligent (d) a definitive utility function. understanding of the environment in whichStatistics(d) the of businesslower quality operates. than Business another economics good. takes the 11. 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The slope of a curve is defined as the change in the value of the variable on the y-axis divided by the (a) Type of cumulative frequency 6. distribution A normal good is(a) a goodWhat for are which the main sources of secondary (d) preferences are complete. ∅y change in thein whichvalue ofclass the intervalsvariable onare the added x-axis. in(a) Thetop there formulato are very for slopefewdata? complements. is , where D means ‘change 12. Indifference curves cannot slope upward because of the ∅ bottom order is classified as (b) demand decreases whenx income increases. assumption that in’. A curve has a varying slope, which can be calculated by drawing(b) Draw a straight a line line graph tangent from to the the following curve data: (i) variation distribution at that point and then calculating the slope of the(c) line. demand To calculate increasesYear the1924 whenslope 1925 ofincome the 1926 curve increases. 1927 at any 1928 point, 1929 1930 (a) MRS is in absolute value. we draw a straight(ii) less line than tangent type distributionto the curve at that(d) point there and are then few calculate substitutes. the slope of the line. We can (b) more is preferred to less Monthly 609 522 205 608 551 632 516 take example(iii) of total more cost than curve, type distributionwhich is 7. first An inverted increase U-shaped in demand and combinedthen U-shaped. with noWe calculatechange in the (c) preferences are transitive. slope of the curve at two different points in Figure 1. Average (iv) marginal distribution supply causes (d) preferences are complete. (b) What areTo thetal costdifferences between an attribute Production © Oxford(a) a decrease University in demandB because Press. the supply All curverights reserved. 13. Marginal utility refers to and a variable? does not shift. Or, The mean age of a group of people is 30 (a) the additional product produced as the firm adds Or years. If the mean age of men is 32 and that (b) the equilibriumD price to fall. one additional unit of an input. What is the most appropriate measure of of women is 27 in the group, find out the Microeconomics.indb 13 central tendency when the data has outliers? percentage of men and women in the group. 6/21/2017 6:43:22 PM C (c) The mean of 100 observations is 50 and their (c) While calculating the mean and variance of 10 standard deviation is 5. The sum of all squares readings, a student wrongly used the reading of all the observations is 52 for the correct reading 25. He obtained the

(i) 50000 Economics_Question_Bank_Part1.indd(iii) 252500 135mean and variance as 45 and 16 respectively. 6/21/2017 6:38:50 PM FEA HGTotalFind output the correct mean and the variance (ii) 250000 (iv) 255000 Figure 1 Slope of the total cost curve Or (d) Moment about mean which is indication whether distribution is symmetrical or There were five customer service representatives asymmetrical is considered as on duty at the Electronic Super Store during last weekend’s sale. The numbers of HDTVs (i) first moment Economics_Part I_Solved_Model_Questions_2014.indd 1 these representatives sold are:6/14/2017 5, 8, 4, 11:03:3710, and AM (ii) third moment 3. Calculate mean deviation. (iii) second moment (d) Prove that the coefficient of skewness is the (iv) fourth moment 3rd order standardized raw moment. Or, Or Explain D5 in terms of , , , … y0 y0 y1 y2 If y is a polynomial of nth degree and the nth Or, Form a simple frequency distribution with differences are constant, what will be the value the following: of differences of higher order? 7,4,3,5,6,3,3,2,4,3,4,3,3,4,4,3,2,2,4,3,5,4,3,4, (e) State Lagrange’s interpolation formula. 3,4,3,1,2,3.

Economics_Part II_Model_Questions_1.indd 1 6/14/2017 7:23:49 PM Road Map—University of Calcutta Syllabus Module I: Microeconomics I

UNIT TOPIC DETAILS CHAPTER Unit I Demand and Concept of demand, demand function, law of demand, derivation of 1 consumer individual and market demand curves, shifting of the demand curve; behaviour elasticity of demand.

Consumer behaviour: Marshallian utility approach and indifference 2 curve approach; utility maximization conditions; income– consumption curve (ICC) and price–consumption curve (PCC), derivation of demand curve from PCC. Unit II Production and Production function: Short-run and long-run; relation among total 3 cost product, average product and marginal product, law of returns to a variable factor, law of returns to scale; concepts of isoquant and isocost line; conditions for optimization (graphical approach). Cost: Accounting and economic costs; social andPress private costs; 4 short-run and long-run costs; relation between average and marginal costs; determination of LAC curve from SAC curves, LMC. Unit III Perfect Concept of perfectly competitive market: Assumptions, profit 5 competition maximization conditions; related concepts of total revenue, average revenue and marginal revenue, short-run and long run equilibrium of a firm; determination of short-run supply curve of a firm, measuring producer surplus under perfect competition, Stability analysis— Walrasian and Marshallian, demand supply analysis including impact of taxes Universityand subsidy. Module II: Statistics

UNIT TOPIC DETAILS CHAPTER Unit I Fundamentals Definition of statistics, scope and limitation of statistics, 1 Oxfordattribute and variable, primary and secondary data, method of data collection, tabulation of data, graphs and charts, frequency distribution, diagrammatic presentation of frequency distribution Unit II Measures of Meaning of central tendency, common measures – mean (AM, GM, 2 central tendency HM), median, and mode, Partition values—quartiles, deciles, and percentiles, applications of different measures. Unit III Measures of Meaning of dispersion, common measures—range, quartile 3 dispersion deviation, mean deviation, and standard deviation; relative measures of dispersion, combined standard deviation, applications of different measures. Unit IV Moments, Different types of moments and their relationships, meaning of 4 skewness, and skewness and kurtosis, different measures of skewness, measure kurtosis of kurtosis, applications of different measures. Unit V Interpolation Finite differences, polynomial function, Newton’s forward and 5 backward interpolation formula, Lagrange’s interpolation formula.

Microeconomics.indb 14 6/21/2017 6:43:23 PM CHAPTER 1 Basics of Demand

This chapter provides the ideas about the concept of demand, law of demand, factors determining demand and demand function. It discusses construction of demand schedule and derivation of individual and market demand curve. The chapter elaborates the difference between movements along the demand curve and shifting of demand curve. It states the situations of exceptions to the law of demand. Press

1.1 Introduction One of the best ways to start discussing about the fundamentals of economics is to begin with the basics of demand and supply. Supply–Demand analysis is a fundamental and powerful tool that can be applied to a wide variety of important problems of economics. We try to ascertain how demand and supply curves areUniversity used to describe the market mechanism. Supply and demand come into equilibrium to determine both market price of a good and the total quantity produced. What the market price and quantity will be depends on the particular characteristics of supply and demand. We will therefore discuss the basic concepts and characteristics of supply and demand in this chapter. Oxford 1.2 Demand Function Demand is the consumer’s willingness to get goods or service in exchange for a price. In other words, demand is a quantity of a commodity the consumer wants to purchase at a given price income situation. Demand depends on many factors. The functional relationship between the quantity demanded for a commodity and its determining factors is known as the demand function. Demand function is the behavioural relationship between quantity demanded for a good or service and all the factors that influence the demand for that good or service. The major factors affecting the demand for a certain good or service are own price of the good or service, price of a substitute or complement of the good or service, personal disposable income, tastes and preferences, and consumer’s expectations about future prices and future income. The functional relationship between quantity demanded and its determinants is called the demand function.

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Demand function can be written as follows: / QD = f(P, P , YD, T, EP, Ey) (1.1) where P = own price of the good or service, P/ = price of a substitute or complement of the good or service YD = personal disposable income, T = tastes and preferences, EP = expectations about future prices, and Ey = expectations about future income. The factors affecting demand are as follows. Own price of the good or service The basic demand relationship is between different prices of a good or service and the quantities that would be purchased at those prices. Generally, such a relationship is negative, that is, an increase in price will induce a decrease in the quantity demanded. Price of related goods or services Related goods of the primary good are of two types, that is, complements and substitutes. Complements are goods that are used with the primary good. For example, tea and sugar are complementary goods. To consume tea, one must also consume sugar. If the price of sugar goes up, the quantity demanded for tea goes down automatically. The mathematical relationship between the price of the complementPress and the demand for the good in question, is negative. The other main category of related goods is substitute. Substitutes are goods that can be used in place of the primary good. For example, tea and coffee. Coffee can be consumed in place of tea. Therefore, if the price of coffee goes down, people will start consuming more coffee and automatically demand for tea will go down. The mathematical relationship between the price of the substitute and the demand for the good in question, is positive. Consumers’ income In general,University the more income (income after tax) a person has, the more likely that person is willing to buy the particular good or service. Therefore, the mathematical relationship between income and the demand for the good or service in question, is positive.

Tastes and preferences How much of a particular good or service is demanded also depends on an individual’s taste and preference for the item. In general, economists use the term ‘tastes and preferences’Oxford as a comprehensive category for a consumer’s attitude towards a product. In this sense, if due to a change in fashion, habit etc., a consumer’s taste and preference for a particular good or service increases, the quantity demanded increases, and vice versa. Therefore, the mathematical relationship between tastes and preferences for a good or service and the demand for the good or service in question is positive.

Consumer’s expectations about future prices and income If a consumer believes that the price of the good or service will be higher in the future, he/she is more likely to purchase the good or service now. Therefore, the mathematical relationship between the consumer’s expectations about future prices of the good or service and the demand for the good or service is positive. If the consumer expects that his/her income will be higher in the future, the consumer is less likely to buy the good or service now.

In Eq. (1.1), dQD/dP < 0 (since, mathematical relationship between the price of the good / and the demand for it, is negative), dQD/dP > 0 for substitute (since, mathematical relationship

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between the price of the substitute and the demand for the good in question, is positive), dQD/ dP/ < 0 for complement (since, mathematical relationship between the price of the complement and the demand for the good in question is, negative), dQD/dYD > 0 (since, mathematical relationship between the income of the consumer and the demand for the good, is positive), dQD/ dT > 0 (since, mathematical relationship between the tastes and preferences for the good and the demand for the good, is positive), dQD/dEP > 0 (since, mathematical relationship between expectations about future prices and the demand for the good, is positive), and dQD/dEY < 0 (since, mathematical relationship between expectations about future income and the demand for the good, is negative).1

1.3 The Law of Demand Demand for a commodity depends on so many factors such as its own price, price of other commodities, and so on. The law of demand states that the quantity demanded for a commodity increases when its price falls and vice versa, if all other factors remain the same. The inverse relation between quantity demanded for a commodity and its own price under ceteris paribus assumption is known as the law of demand. Press In other words, the law of demand states that the quantity demanded and the price of a commodity are inversely related, other things remaining constant. All the goods, for which law of demand is applicable, are called normal goods. The reason behind the inverse relationship between quantity demanded and price for a normal good is quite simple. People have limited incomes. Suppose, a consumer purchases 1 kg of apple for consumption of his/her family for 1 week. If the price of apple goes up, the weekly expenditure of the consumer for apple will also go up if he/she continues to purchase the same quantity after the rise in price. In order to maintain the weekly budget, theUniversity consumer will reduce his/her consumption for apple. The opposite thing will happen if the price of apple goes down. Therefore, it is clear, for normal goods, if price goes up, quantity demanded will go down and vice versa. The geometric representation of price quantity relationship is known as the demand curve. The law of demand suggests that the demand curve for a commodity should be negatively sloped. However, Oxfordlaw of demand implies that changing price would move quantity demanded up or down, but this would not change the demand itself. Change in quantity demanded and change in demand are not the same concept. Change in quantity demanded refers to the change in the amount of a commodity as a result of change in the price of it. Amount demanded rises or falls according to the fall or rise in price. In such a case, other factors influencing demand are held constant. The change takes place in the same demand curve. On the other hand, ‘change in demand’ means changes in demand due to the changes in the factors other than price, for example, income, taste and preference, prices of other related

1 dQD/dP = Change in quantity demanded due to change in own price / dQD/dP = Change in quantity demanded due to change in price of substitute or complement dQD/dYD = Change in quantity demanded due to change in disposable income dQD/dT = Change in quantity demanded due to change in tastes and preferences dQD/dEP = Change in quantity demanded due to change in expectation about future price dQD/dEY = Change in quantity demanded due to change in expectation about future income

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commodities, etc. The change in demand involves ‘increase’ and ‘decrease’ of the demand for a commodity. In case of change in demand the entire demand schedule and demand curve change. With an increase in demand, the curve shifts upwards and with a decrease in demand, the curve shifts downwards.

1.3.1 Demand Schedule A demand schedule is crucial for constructing a demand curve. A demand schedule lists prices and corresponding quantities based on the law of demand. To understand the concept of demand schedule better, let us look at the demand schedule of a popular luxury soap in Table 1.1. Table 1.1 Demand schedule of It exhibits hypothetical demand schedule of an individual for luxury soap a popular luxury soap. We find that there is an inverse relationship between price and quantity demanded because a demand schedule Price (`) Quantity demanded follows the law of demand. 50 1 1.3.2 Derivation of Individual Demand Curve 40 2 We can construct the demand curve of an individual for 30 3 Press a luxury soap based on the demand schedule, as shown in 20 4 Fig. 1.1. While deriving the demand curve, we would always 10 5 measure quantity along the horizontal axis and price along the vertical axis. Demand curve is the locus of all the points Price D showing demand for a good or service at various prices of that 50 good or service. Table 1.1 shows that when the price is `50, the quantity demanded is 1 unit. Similarly, when the price 40 is `University40, the quantity demanded is 2 units, and so on. As we 30 can see, there is a corresponding quantity for each price. By joining all the points established by plotting all prices and their 20 corresponding quantities on a graph, we can obtain a demand 10 D curve. Hence, the demand curve for a normal good exhibits the law of demand, that is, the relationship between two variables, 0 1 2 3 4 Oxford5 Quantity namely price and quantity demanded. Since the demand curve Figure 1.1 Individual demand curve follows the law of demand, it is negatively sloped.

1.3.3 Derivation of Market Demand Curve The previously discussed demand schedule and demand curve are the case of an individual. The analysis can be extended to a market in the same manner. A market typically consists of many customers and different customers possess different tastes and preferences, different incomes, different expectations about future prices and future incomes. Hence, individual demand curves differ from person to person in their slopes and shapes. However, we are able to sum up all individual demand curves and derive a market demand curve. In other words, the market demand curve is the sum of all individual demand curves. For simplicity, let us assume that the market consists of only two customers. Table 1.2 depicts the individual demand schedules of a popular luxury soap for consumer 1 and consumer

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Table 1.2 Individual demand schedules of luxury soap 2 and also the combined demand schedule of the luxury soap for the market. From Table 1.2, we Price (`) Quantity demanded by Market demand of understand that the market demand is obtained Consumer 1 Consumer 2 luxury soap by summing up individual demands. The table ` 50 1 0 1 shows that at price 50, the market demand is 1 unit; at price `40, the market demand is 3 units; 40 2 1 3 at price `30, the market demand is 5 units; and so 30 3 2 5 on. Since there is an inverse relationship between 20 4 3 7 price and quantity demanded, it is obvious that the market demand schedule also follows the law 10 5 4 9 of demand. Similarly, we can derive the market demand curve (D) by the horizontal summation of

individual demand curves (D1 + D2), as illustrated in Fig. 1.2.

Price Price 50 Price 50 Press 40 40 40 30 30 30 20 20 20

10 10 D 10 D1 2 D 0 0 0 1 2 3 4 5 1 2 3 4 1 3 5 7 9 Quantity Quantity (a) (b) (c) Quantity

Figure 1.2 Demand curve (a) Demand curve forUniversity consumer 1 (D1) (b) Demand curve for consumer 2 (D2) and (c) Market demand curve (D1 + D2 = D)

Price 1.3.4 Movement along the Demand Curve D Movement along the demand curve occurs when there is a change in B Oxford P1 the own price. As we know, there is an inverse relationship between price and quantity demanded. Hence, reduction in the price causes a A downward movement. This means that there is an increasing demand. P2 Further, rise in the price causes an upward movement. This means that C P3 D there is a decreasing demand. Movements along the demand curve are shown in Fig. 1.3.

O Q1 Q2 Q3 Quantity In Fig. 1.3, the movement from A to C represents movement Figure 1.3 Movements along the along the demand curve. At point A, the price is OP2 and the quantity demand curve demanded is OQ2. When there is a movement from point A to point C, price falls to OP3 and quantity demanded increases to OQ3. Further, when there is a movement from point A to point B, price rises to OP1 and quantity demanded decreases to OQ1. Here, we can notice that the movement along the demand curve occurs because of a rise or a fall in the price level.

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1.3.5 Shifting of the Demand Curve We have mentioned earlier that there are various determinants of demand for a commodity apart from its price, for example, personal disposable income of the consumer, prices of the related goods and services, preferences of the consumer, etc. A shift in the demand curve occurs when any one of those determinants change. Income of the consumer is one of the determinants of demand. If the household income increases, there is an increase in the demand. This implies that for the same level of price, quantity demanded will be higher and hence the demand curve will Price shift outwards. Outward shifting of the demand curve for increase in

D1 income is shown in Fig. 1.4. Assume that the demand curve (DD) in D Fig. 1.4 refers to demand for tea. Let us consider the income of the consumer as one of the determinants of demand. Suppose income of the consumer increases, then, the consumer’s demand for tea for A B P1 the same price increases. Therefore, the original demand curve for tea

(DD) shifts to the right and forms a new demand curve (D1D1). In D1 D this case, quantity demanded increasesPress from OQ1 to OQ2. However, the price remains unchanged at OP1. O Q1 Q2 Quantity demanded Figure 1.4 Shifting of demand Suppose due to change in fashion or habit, tastes and preference curve due to increase in income of the consumers for the particular commodity increases. This implies that, for the same level of price, quantity demanded will be higher Price and the demand curve will shift outwards. Outward shifting of the

D1 demand curve for the change in tastes and preferences in favour of the D commodity is shown in Fig. 1.5. If tastes and preferences of people have changedUniversity towards the consumption of tea, may be because drinking tea has become a new habit or new fashion, more amount of tea will A B P1 be demanded at the same price level. Hence, the demand curve for

tea (DD) will shift rightwards (to 1D D1). Quantity demanded will D1 D increase from OQ1 to OQ2, whereas price will remain at OP1. Assume that coffee is the substitute and sugar is the complement O Q Q Quantity demanded 1 2 Oxfordof tea. Now, if the price of coffee increases, people will purchase less Figure 1.5 Shifting of demand of coffee and the demand for tea will increase. Hence, demand curve curve due to increase in tastes and preferences for tea will shift outwards. On the other hand, if the price of sugar increases, people will purchase less of sugar. Since tea has to consumed in combination with sugar, demand for tea will decline. Hence demand curve for tea will shift inwards. Outward shifting of the demand curve for increase in the price of the substitute good is shown in Fig. 1.6. On the other hand, shifting of the demand curve due to increase in the price of the complement good is shown in Fig. 1.7.

In Fig. 1.6, demand curve for tea (DD) will shift rightwards (to 1D D1) as a result of increase in price of coffee. Quantity of tea demanded will increase from OQ1 to OQ2, whereas price will remain at OP1. On the other hand, demand for tea will decline for the same price level as a result of increase in the price of sugar, as shown in Fig. 1.7. Hence, demand curve for tea (DD) will shift leftwards

(to D1D1), whereas price will remain the same (at OP1).

Microeconomics.indb 8 6/21/2017 6:43:26 PM Basics of Demand 9

Price Price

D1 D D D1

A B B A P1 P1

D1 D

D D1

O Q1 Q2 Quantity demanded O Q2 Q1 Quantity demanded Figure 1.6 Shifting of demand Figure 1.7 Shifting of demand curve due to increase in the price curve due to increase in the price of substitute good of complement good

1.4 Exceptions to the Law of Demand For most of the goods and services, according to the law of demand, the quantity demanded for a good increases with a decrease in price of the goodPress and vice versa. Such goods and services are called normal goods and services. Demand curve for a normal good or service follows the law of demand and therefore it is downward sloping. In some cases, however, this may not be true. The circumstances when the law of demand becomes ineffective are known as exceptions of the law of demand. In those cases, the demand curve does not follow the law of demand and therefore it is not downward sloping. Such situations are explained in the following subsections. 1.4.1 Giffen Goods University Some special varieties of inferior goods are termed as Giffen goods. Cheaper varieties of this category like bajra, cheaper vegetable like potato come under this category. Sir Robert Giffen from Ireland first observed that people used to spend more of their income on inferior goods like potato and less of their income on meat. However, potatoes constituted their staple food. When the priceOxford of potato increased, after purchasing potato they did not have so many surpluses to buy meat. So the rise in the price of potato compelled people to buy more potato and thus

Price D raised the demand for potato. Hence, demand curves for Giffen goods are positively sloped as shown in Fig. 1.8. This is against the law of demand. This is also known as Giffen paradox. 1.4.2 Conspicuous Consumption This exception to the law of demand is associated with the doctrine propounded by Thorsten Veblen. A few goods like diamonds, are purchased by the rich and wealthy sections of the society. The prices of D these goods are so high that they are beyond the reach of the common O Quantity demanded man. The higher the price of the diamond, the higher the prestige value Figure 1.8 Demand curve in of it. So when price of these goods falls, the consumers think that the case of Giffen good prestige value of these goods comes down. So quantity demanded of

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Demand curve in case of these goods falls with fall in their price. So the law of demand does not conspicuous consumption Price hold good here. Here also, the demand curve is positively sloped as D shown in Fig. 1.9.

1.4.3 Conspicuous Necessities Certain things become the necessities of modern life. So we have to purchase them despite their high price. The demand for T.V. sets, automobiles, and refrigerators has not gone down in spite of the increase

D in their price. These things have become the symbol of status. So they are purchased despite their rising price. These can be termed as ‘U’ O Quantity demanded sector goods. When quantity demanded for these goods increases despite Figure 1.9 Demand curve increase in price, the demand curves for such goods are positively sloped. in case of conspicuous Again, when quantity demanded for these goods remains constant despite consumption increase in price, the demand curves for such goods are vertical. These cases are shown in Figs 1.10 and 1.11.

Price PressPrice D D

D University D

O Quantity demanded O Quantity demanded Figure 1.10 Demand curve in case of Figure 1.11 Demand curve in case of conspicuous necessities (increasing conspicuous necessities (increasing prices andOxford increasing demand) prices and constant demand) 1.4.4 Ignorance Price D A consumer’s ignorance is another factor that at times induces him to purchase more of the commodity at a higher price. This is especially so when the consumer is haunted by the phobia that a high-priced commodity is better in quality than a low-priced one. Once again, in this case, the demand curve is positively sloped, as shown in Fig. 1.12.

D 1.4.5 Emergencies

O Quantity demanded Emergencies such as war and famine negate the operation of the law of Figure 1.12 Demand curve demand. At such times, households behave in an abnormal way. Households in case of ignorance about the make more prominent and induce further price rises by making increased commodity purchases even at higher prices during such periods. During depression, on

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Price the other hand, no fall in price is a sufficient inducement for consumers to D demand more. The demand curves for all essential commodities become positively sloped under these circumstances, as shown in Fig. 1.13. 1.4.6 Future Changes in Prices Households also act as speculators. When the prices are rising, households D tend to purchase large quantities of the commodity out of the apprehension that prices may still go up. When prices are expected to fall further, they O Quantity demanded wait to buy goods in future at still lower prices. So quantity demanded Figure 1.13 Demand curve in falls when prices are falling. The demand curve becomes positively sloped case of emergencies in such situations, as shown in Fig. 1.14. 1.4.7 Change in Fashion A change in fashion and tastes affects the market for a commodity. When a long skirt replaces a short skirt, no amount of reduction in the price of the latter is sufficient to clear the stocks, that is, demand for short skirts falls with reduction in the price of short skirts. Long skirt on the other hand will have more customers even though its pricePress may be going up, that is demand for long skirts increases with the increase in price of long skirts. The law of demand becomes ineffective. Under these circumstances, demand curve for both the long skirt and the short skirt becomes positively sloped, as shown is Fig. 1.15.

Price Price D D University

D D O Quantity demanded O Quantity demanded Figure 1.14Oxford Demand curve in case of Figure 1.15 Demand curve in speculations about future changes in prices case of changes in fashion

1.5 Elasticity of Demand Now, we would like to check how demand of any commodity responds to changes in its main determinants, that is, price of the commodity, price of any related commodity, and income, other things remaining the same. Rate of change in demand for any commodity due to 1 per cent change in any of the determinants of demand is called elasticity of demand. We will discuss about own price elasticity of demand, cross-price elasticity of demand, and income elasticity of demand. 1.5.1 Own Price Elasticity of Demand Own price elasticity of demand is the percentage change in demand for any commodity due to 1 per cent change in its own price, other things remaining the same. Own price elasticity of

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demand (ep) for commodity X1 can be expressed as follows:

Percentage change in demand for the commodity X1 e p = Percentagge change in P1 Change in demand for the commodity X1 Initiall quantity demanded of = X1 Change in P1 Initial level of P1 If we denote change by ∅, the absolute value of own price elasticity of demand is

∆X1 X P ∅X ||= 1 = 1 . 1 (1.2) e p ∆ P1 X1 ∅P1 P1 Value of own price elasticity of demand will depend upon the type of good we are talking about, as discussed here. Press • If the good is a normal good, then there will be a negative relationship between quantity demand and price, that is, ∆∆XP11< 0/ , (P1 > 0 and X1 > 0). Therefore, own price elasticity of demand for normal good will be negative. • In case of a normal necessity good, change in quantity demanded will be less than that in price, that is, own price elasticity of demand for normal necessity good will be negative and its absolute value will be less than one. • In case of a normal luxury good, change in quantity demanded will be more than that in price, that is, own price elasticityUniversity of demand for normal luxury good will be negative and its absolute value will be greater than one. • In case of an inferior good, change in quantity demanded will be less than that in price, that is, own price elasticity of demand for inferior good will be negative and its absolute value will be less than one. • In case of aOxford Giffen good, there will be a positive relationship between quantity demand and price, that is, ∆∆XP11> 0/ , (P1 > 0 and X1 > 0). Therefore, own price elasticity of demand for Giffen good will be positive.

1.5.2 Measurement of Own Price Elasticity of Demand Own price elasticity can be measured in two ways. Firstly, when change in own price is bigger, the change of quantity demanded will be a measurable portion of the demand curve, which can be called an arc. Therefore, it is called arc elasticity of demand. Secondly, when change in price is very small, the change in quantity demanded cannot be easily measurable on the demand curve. Therefore, it is called point elasticity of demand. Arc Elasticity of Demand

In Fig. 1.16, as price falls from P1 to P2, quantity demanded increases from X1 to X2. Equilibrium point changes from E1 to E2. Distance E1E2 is measurable and it is an arc. We have to measure

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Price of X elasticity on this arc. If we consider P1 the initial price DD and X1 the initial quantity demanded, change is price is P2 − P1 and change is quantity demanded is X2 − X1. Arc elasticity of demand is

Change in quantity demanded E1 Original quantity demanded P1 Earc = CChange in own price original own price

E2 − (1.3) P2 XX21 P XX− = X1 = 1 ⋅ 21 − PP21 X1 PP21− P 1

If we consider P2 the initial price and X2 the initial 0 X1 X1 Quantity of X quantity demanded, change is price is P1 − P2 and Fig. 1.16 Arc elasticity of demand change is quantity demanded is X1 − X2. Arc elasticity of demand is Press Change in quantity demanded Original quantity demanded Earc = CChange in own price Original own price

XX12− (1.4) P XXX− X2 =⋅2 12 − PP12 X2 PP12− P 2 University If we compare these two values of arc elasticity, XX− XX− 21= 12 PP21− PP12− However, Oxford P P 1 ↑ 2 X1 X2 Therefore, if we measure the arc elasticity from two opposite side, values will be different. To solve this problem, we consider the average value of both price and quantity as initial price and quantity. Therefore,

XX12− XX12+ 2()XX− PP+ PP+ XX− E = 2 = 12⋅ 12= 12⋅ 12 (1.5) arc − PP12 XX12+ 2()PP12− X1 ++ X2 PP12− PP12+ 2

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PP+ 12> 0 XX12+ XX− However, 12< 0 PP12−

Since PP12−>0 and XX12−<0 .

Therefore,E arc < 0. Point Elasticity of Demand When change in price is very small, resulting change in quantity demanded is also very small. In this situation, the initial equilibrium point and the final equilibrium point come close to each other, that is, the arc becomes smaller. Ultimately, the two equilibrium points tend to coincide. As a result, the arc becomes a point. Therefore, the arc elasticity becomes point elasticity. Thus, the limiting value of arc elasticity is the point elasticity.

If we assume that we have to measure elasticity at point (P0, X0), then absolute value of point elasticity is Press Change in quantity demanded Original quuantity demanded Own price elasticity = Change in own price Original own price

P00 dX Ep = ⋅ (()Change is denoted by d, since change is very small X0 dP

As dX/ dP < 0 , value of Ep is negative. Our problem is to measure priceUniversity elasticity at a point on the demand curve. This is illustrated in Fig. 1.17. We have to measure point price elasticity at point C, where price level is OE and quantity demanded is OD. Price of X P0 dX A Price elasticity = . Oxford X0 dP We know that, P OE 0 = E C X0 OD Now, we have to find out, dX/ dP . We know that the demand function is X = f(P). Therefore, inverse demand function can be written asP = F(X). B From the inverse demand function, we obtain the slope of the 0 D Quantity of X demand curve as Fig. 1.17 Measurement of price dP Perpendicular OA CD AE AE elasticity at a point on the demand = = = = = (since EC = OD) curve dX Base OB DB EC OD

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Therefore, OE OD OE BD BC Point price elasticity at point C = .=== OD AE AE OD AC

If point C is the mid-point of the demand curve, BC = AC. Therefore,E p = 1.

If the point lies on the upper half of the demand curve, BC > AC, therefore, Ep > 1.

If the point lies on the lower half of the demand curve, BC < AC, therefore, Ep < 1. Point price elasticity at point A is ∞, since denominator = 0. Point price elasticity at point B is 0, since numerator = 0.

1.5.3 Elastic and Inelastic Demand The shape of any demand curve depends upon the absolute value of elasticity of demand. The shapes of different demand curves according to the absolute values of elasticity of demand are explained as follows: • When price elasticity of demand is less than one, it is called inelastic demand, as in case of necessity goods. Such a demand curve is shown in Fig. 1.18.Press • When price elasticity of demand is more than one, it is called elastic demand, as in case of luxury goods. Such a demand curve is shown in Fig. 1.19.

Price Price D D P1 UniversityP1 P2 P2

D OxfordD 0 Q1 Q2 Quantity 0 Q1 Q2 Quantity Fig. 1.18 Inelastic demand curve Fig. 1.19 Elastic demand curve

• When price elasticity of demand is equal to one, it is called unitary elastic demand. Such a demand curve is shown in Fig. 1.20. • When price elasticity of demand is equal to ∞, it is called perfectly elastic demand. The shape of a perfectly elastic demand curve is horizontal. Such a demand curve is shown in Fig. 1.21. • When price elasticity of demand is equal to 0, it is called perfectly inelastic demand. The shape of a perfectly inelastic demand curve is vertical. Such a demand curve is shown in Fig. 1.22.

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Price Price Price D

P1 D D P2 P

D 0 Q Q Quantity 0 Quantity 1 2 0 Q0 Quantity Fig. 1.21 Perfectly elastic Fig. 1.20 Unitary elastic demand Fig. 1.22 Perfectly inelastic demand curve curve demand curve

1.5.4 Distinction between Slope of a Demand Curve and Elasticity of Demand Slope of the demand curve and elasticity of demand are twoPress different concepts. Inverse demand function is P = F(X). From this inverse demand function, we get the slope of the demand curve as dP/ dX . On the other hand, price elasticity of demand is P P dX ⋅ or X X dP dP dX University Therefore, we can say that elasticity of demand and slope of the demand curve are not the same. Price of X We can show that, • Two demand curves can have the same slope but their elasticities A 1 Oxfordcan be different. A • Two demand curves can have different slopes but their elasticities can be same. • The higher the slope of the demand curve, the lower will be the elasticity and vice versa. D It can be shown that two demand curves can have the same slope, C C1 but elasticities of demand can be different.

In Fig. 1.23, two demand curves AB and A1B1 are parallel to each other. For price level OD, we have equilibrium point C on AB and 0 B B1 equivalent equilibrium point C1 on A1B1. Since two demand curves Quantity of X AB and A1B1 are parallel to each other, Fig. 1.23 Demand curves with OA OA same slope but different elasticities = 1 of demand OB OB1

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Therefore,AB and A1B1 have the same slope. We have to find out the elasticity of demand for these two demand curves at two equivalent

equilibrium points C and C1. BC OD Elasticity of demand at C = = CA DA

BC11 OD Elasticity of demand at C1= = CA11 DA1

Since, DA1 > DA, OD OD < DA1 DA

Therefore, elasticity of demand ofAB at point C is greater than that of A1B1 at point C1. It can also be shown that two demand curves can have the same elasticity of demand, but their slopes can be different. In the first part of Fig. 1.24, we have two demand curvesPress AB and AC with same vertical intercept. If we try to measure elasticity of demand on two equivalent points H and I, we see that BH OG At point H, elasticity of demand is = HA GA Again, CI OG Elasticity of demand at pointUniversity I is = IA GA Therefore, elasticity of demand at pointH is the same as elasticity of demand at point I.

Price of X Price of X Oxford D A

J D1

G K H I

L 0 B C 0 E Quantity of X Quantity of X Fig. 1.24 Two demand curves with same elasticity of demand, but different slopes

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On the other hand, slope of demand curve AB is OA/ OB and slope of demand curve AC is OA/ OC Since, OC > OB, slope of demand curve AB is clearly greater than that of AC. In the second part of Fig. 1.24, we have two demand curves DE and D1E with same horizontal intercept. If we try to measure elasticity of demand on two equivalent points J and K, we see that At point J, elasticity of demand is EJ EL = JD LO Again, elasticity of demand at point K is EK EL = KD1 LO

Clearly, elasticity of demand at two equivalent points on DE and D1E are the same. On the other hand, slope of demand curve DE is OD/ OE and slope of demand curve D1E is OD1/ OE . Since, OD > OD1, slope of demand curve DE is clearly greater than that of D1E. We can also prove that Pressthe higher the slope of the demand Price of X curve, the lower will be the elasticity and vice versa. A In Fig. 1.25, two demand curves AB and CD intersect each other at point E. If we compare the values of elasticity of demand at their intersection point E, we get C Elasticity of demand at point E for the demand curve AB = BE/EA = OF/FA Elasticity of demand at point E for the demand curve F E CDUniversity = DE/EC = OF/FC Since FA > FC, elasticity of demand at point E for AB is clearly less than elasticity of demand at point E for CD. Slope of AB = OA/OB and slope of CD = OC/OD OBD It is evident that OA/OB is greater than OC/OD, that is, Quantity ofOxford X slope of AB is greater than that of CD. Fig. 1.25 Elasticity of demand at the Hence, if slope of AB is greater than that of CD, it is proved point of intersection of two demand that elasticity of demand at any point on AB is less than elasticity curves of demand at the equivalent point on CD. 1.5.5 Cross-price Elasticity of Demand The rate of change in demand for any commodity due to 1 per cent change in any of the determinants of demand is called elasticity of demand. The main determinants of demand are price of the commodity, price of any related commodity, income of the consumer, tastes and preferences, future expectations about prices, and future expectations about income. We have already discussed about own price elasticity of demand. Now, we would like to know how demand for a commodity responds to the changes in the price of a related commodity. Cross-price elasticity of demand is the percentage change in demand for any commodity due to 1 per cent change in the price of a related commodity, other things remaining the same.

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Cross-price elasticity of demand (ec1) for commodity X1 can be expressed as follows:

Percentage change in demand for the commodity X1 ec1 = Percentaage change in P2 Change in demand for the commodity X1 Initiaal quantity demanded of = X1 Change in P2 Initial level of P2 If we denote change by ∅, we can write

∆X1 X P ∆X ==1 2 . 1 (1.6) ec1 ∆ P2 X1 ∆P2 P2

Both P2 and X1 are positive. Therefore, sign of cross elasticity of demand for X1 will depend on ∅X ∅X 1 . Again, sign of 1 will depend upon the nature of relationship between the commodities ∅P2 ∅P2 Press X1 and X2. As price of X2, that is, P2, increases, demand for X2 decreases. • If the two commodities X1 and X2 are substitutes to each other, as demand for X2 decreases, demand for X1 increases. In short, as P2 increases, demand for X1 increases and vice versa. Therefore, the sign of cross elasticity of demand forX 1, that is, ec1, is positive. • If the two commodities X1 and X2 are complements to each other, as demand for X2 decreases, demand for X1 also decreases. In short, as P2 increases, demand for X1 decreases and vice versa. Therefore, the sign of cross elasticity of demand forX 1, that is, ec1, is negative. University

• If the two commodities are completely unrelated to each other, as demand for X2 decreases, there is no change in demand for X1. In short, as P2 increases or decreases, demand for X1 does not change at all. Therefore, cross elasticity of demand forX 1, that is, ec1, is zero. 1.5.6 IncomeOxford Elasticity of Demand We have already discussed about own price elasticity of demand and cross-price elasticity of demand. Now we would like to know how demand for a commodity responds to the changes in the income of the consumer. Income elasticity of demand is the percentage change in demand for any commodity due to 1 per cent change in the income (M) of the consumer, other things remaining the same. Income elasticity of demand (em) for commodity X1 can be expressed as follows:

Percentage change in demand for the commodity X1 e = m Percentagge change in income M Change in demand for the commodity X1 IInitial quantity demanded of = X1 Change in M Initial level of M

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If we denote change by ∅, we can write

∆X1 X M ∆X ==1 . 1 (1.7) em ∆ M X1 ∆M M

Both M and X1 are positive. Therefore, the sign of income elasticity of demand forX 1 will depend on ∅∅XM1/ .

• If X1 is a normal good, as income increases, demand for X1 increases. Therefore, in case of a normal good, ∆∆XM1 > 0/ , that is, income elasticity of demand or em > 0. • If X1 is a normal necessity good, as income increases, demand for X1 increases, but at a lower rate than the rate of increase in income. Therefore, in case of a normal necessity good,

∆∆XM1 <1/ , that is, income elasticity of demand or em <1. • If X1 is a normal luxury good, as income increases, demand for X1 increases, but at a faster rate than the rate of increase in income. Therefore, in case of a normal luxury good, ∆∆XM1 >1/ > , that is, income elasticity of demand or em 1. Press • If X1 is an inferior good or a Giffen good, as income increases, demand for X1 decreases. Therefore, in case of an inferior good or a Giffen good or a Giffen good, ∆∆XM1 < 0/ , that is, income elasticity of demand or em < 0. 1.5.7 Measurement of Income Elasticity of Demand To measure income elasticity of demand, we have to describe the concept of Engel curve. Engel curve is the locus of different amounts of a particular commodity that the consumer purchases at different levels of income. At Universitydifferent points on the Engel curve, we can measure the income elasticity of demand for a commodity. In Fig. 1.26, we measure money income of the consumer along the horizontal axis and

quantity demanded of commodity X1 along the vertical axis. AB is the Engel curve in the figure. 0 For income level OD, demand for commodity X1 is OX1 . We have to measure income elasticity of demand for X1 at point C. Quantity of commodity XOxford1 A At point C,

M ∆X1 1 E e = . X1 m X1 ∆M Now, C 0 X1 M OD OD =0 = X1 OX1 CD Again, ∆X 1 = Slope of the Engel curve at point C = B D F ∆M 0 Money income of the consumer (M) Perpendicular CD = Fig. 1.26 Engel curve Base BD

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Quantity of commodity X1 Therefore, at pointC , A M ∆X1 OD CD OD em ==. .= X1 ∆M CD BD BD C Similarly, at point E, B M ∆X1 OF EF OF em ==. .= X1 ∆M EF BF BF The Engel curve AB is positively sloped. Therefore, it is clear that as income increases, consumer demand for X1 increases. Therefore,e m is positive. Moreover, since, Engel curve AB has ODE a positive intercept in the horizontal axis, that is, when income Money income of the consumer (M) is OB, the demand for commodity X1 is zero, OD > BD, and Fig. 1.27 Engel curve with zero intercept also OF > BF. Therefore,e m is always greater than one for commodity X1. In Fig. 1.27, Engel curvePress OA has zero intercept in the horizontal axis, that is, it passes through the origin. In other words, when income is zero, demand

for commodity X1 is also zero. Under these circumstances, M OD ∆X BD = and 1 = X1 BD ∆M OD Therefore, at pointB ,

M ∆X1 OD BD em ==..University=1 X1 ∆M BD OD

Similarly, at point C or at any other point on the Engel curve OA, em = 1. In Fig. 1.28, Engel curve AB has a negative intercept in the horizontal axis, that is, when income is zero, the demand for commodity X1 is OC, that is, positive. Therefore,Oxford at pointD ,

Quantity of commodity X1 OF em =<1 A BF E In addition, at point E, D OG em =<1 BG

C Similarly, at any other point on the Engel curve AB, em < 1. In Fig. 1.29, Engel curve AB is an upward rising curve. To B0 FG measure income elasticity of demand for X1, at any point, say E, Money income of the consumer (M) on the curve AB, we have to draw a tangent of the curve through Fig. 1.28 Engel curve with negative point E. Slope of the curve AB at point E is the slope of the tangent Price of X intercept CD at point E, that is, Price of. X D A © Oxford University Press. All rights reserved.

D J Microeconomics.indb 21 6/21/20171 6:44:11 PM

G K H I

L 0 B C 0 E Quantity of X Quantity of X 22 Microeconomics 1 and Statistics

Quantity of commodity X1 Quantity of commodity X1 A A C

C E

0FD 0 D B Money income of the consumer (M) Money income of the consumer (M) Fig. 1.29 Upward rising Engel curve Fig. 1.30 Downward or negative slope of Engel curve Therefore, at pointE , Press

M ∆X1 OF EF OF em ==..= X1 ∆M EF DF DF

If the commodity X1 is an inferior good, then as income increases, demand for commodity X1 decreases. Therefore, Engel curve for commodity X1 will slope negatively as shown in Fig. 1.30. In Fig. 1.30, the Engel curve AB is a negatively sloped straight line. At point C, M OD ∆X CD = and 1 =− X1 CD ∆M UniversityDB Therefore, at pointC ,

M ∆X1 OD CD OD em ==..−=− X1 ∆M CD DB DB Hence, atOxford any other point on the Engel curve AB, em < 0.

SUMMARY • Demand is a consumer’s readiness and capability to disposable income of the consumer, prices of the pay a price for a specific quantity of a good or service related goods and services, preferences of the at a given point of time. The relationship between consumer, and expectations about the future prices price and quantity demanded is known as the demand and income. relationship. The law of demand states that the quantity • Demand function is the behavioural relationship demanded and the price of a commodity are inversely between quantity demanded for a good or service related, other things remaining constant. All the goods, and all the factors that influence the demand for that for which law of demand is applicable, are called normal good or service. goods. • A demand schedule lists prices and corresponding • Demand for certain good or service depends on a quantities based on law of demand. We can construct number of different factors, for example, personal the demand curve of an individual based on the demand

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schedule. Demand curve is the locus of all the price– cent change in its own price, other things remaining quantity combinations which follow the law of demand. the same. Since the demand curve follows the law of demand, • Own price elasticity can be measured in two ways. it is negatively sloped. Firstly, when change in own price is bigger, the • Individual demand curves differ from person to change of quantity demanded will be a measurable person in their slopes and shapes. We can sum up portion of the demand curve, which can be called an all individual demand curves and derive a market arc. Therefore, it is called arc elasticity of demand. demand curve. Secondly, when change in price is very small, the • Movement along the demand curve occurs when change in quantity demanded cannot be easily there is a change in the own price. There are various measurable on the demand curve. Therefore, it is determinants of demand for a commodity apart from called point elasticity of demand. its price, for example, personal disposable income • The elasticity of demand and slope of the demand of the consumer, prices of the related goods and curve are not same. services, preferences of the consumer, etc. A shift • The cross-price elasticity of demand is the percentage in the demand curve occurs when any one of those change in demand for any commodity due to 1 per determinants change. cent change in the price of a related commodity, other • The circumstances when the law of demand becomes things remaining the same. ineffective are known as exceptions of the law of • Income elasticity of demand is the percentage change demand. In those cases, the demand curve does in demand for any commodity due to 1 per cent change not follow the law of demand and therefore it is not in the income of Pressthe consumer, other things remaining downward sloping. the same. • The rate of change in demand for any commodity due • Engel curve is the locus of different amounts of a to 1 per cent change in any of the determinants of particular commodity that the consumer purchases at demand is called elasticity of demand. different levels of income. At different points on the • Own price elasticity of demand is the percentage Engel curve, we can measure the income elasticity change in demand for any commodity due to 1 per of demand for a commodity. University

EXERCISES

[According to CU syllabus of Economic-I paper for B Com Honours and General, second unit requires three lectures and four marks. Therefore, we have incorporated Oxfordthe short-answer type questions carrying two marks and medium-answer type questions carrying four marks in the exercise.] SHORT-ANSWER TYPE QUESTIONS (2 MARKS) 1. What do you mean by demand? 8. What is the relation between demand for a good and the 2. What is law of demand? price of its complement? 3. State the law of demand. Mention any two exceptions to 9. What is the relation between demand for a good and the this law. [CU B Com (G), 2012] income of the consumer? 4. What do you mean by a normal good? 10. What is the relation between demand for a good and the 5. Mention the factors determining demand. tastes and preferences of the consumers? 6. What is the relation between demand for a good and its 11. What is the relation between demand for a good and own price? future expectations of the consumer about the price of 7. What is the relation between demand for a good and the the good? price of its substitute?

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12. What is the relation between demand for a good and the 37. What will be the value of own price elasticity of demand future expectations of the consumer about his/her income? for an inferior good? 13. What is meant by a demand function? 38. What will be the value of own price elasticity of demand [CU B Com (G), 2005] for a Giffen good? 14. State the demand function in its general form. 39. What is elastic demand? 15. What do you mean by a demand schedule? 40. What is inelastic demand? 16. What is the shape of the demand curve for a normal good? 41. What is the shape of a perfectly elastic demand curve? 17. What is market demand? 42. What is the shape of a perfectly inelastic demand curve? 18. How can market demand be derived from individual 43. At which point on a downward sloping straight line demand? [CU B Com (G), 2012] demand curve the absolute value of the price-elasticity of 19. Under what circumstances does the demand curve shift? demand is unity? [CU B Com (G), 2007] [CU B Com (G), 2005] 44. What is meant by ‘cross-price elasticity of demand’? 20. How will the demand curve change with the increase in [CU B Com (G), 2010] income of the consumer? [CU B Com (G), 2005] 45. If the cross-price elasticity of two related goods is 21. Mention two cases where the consumer demand curve positive, what is the relationship between the aforesaid shifts upwards. [CU B Com (G), 2009] goods? [CU B Com (G), 2008] 22. What is the shape of the demand curve in case of Giffen 46. If the cross-price elasticity of two related goods negative, goods? what is the relationshipPress between the aforesaid goods? 23. What is the shape of the demand curve in case of 47. If the cross-price elasticity of two goods is zero, what is conspicuous consumption? the relationship between the aforesaid goods? 24. What is the shape of the demand curve in case of 48. What do you mean by income elasticity of demand? conspicuous necessities? 49. What will be the value of income elasticity of demand for 25. What is the shape of the demand curve in case of a normal good? ignorance of the consumers? 50. What will be the value of income elasticity of demand for 26. What is the shape of the demand curve in case of a normal necessity good? emergencies? University51. What will be the value of income elasticity of demand for 27. What is the shape of the demand curve in case of a future a normal luxury good? expectation of price rise? 52. What will be the value of income elasticity of demand for 28. What is the shape of the demand curve in case of a future an inferior good? expectation of fall in price? 53. What will be the value of income elasticity of demand for 29. What is the shape of the demand curve in case of a a Giffen good? change in fashion? 54. What is an Engel curve? 30. What do you mean by elasticityOxford of demand? 55. If the Engel curve is upward rising with a positive 31. What do you mean by price elasticity of demand? intercept on the horizontal axis, what will be value of [CU B Com (G), 2009] income elasticity of demand at any point on the curve? 32. What is own price elasticity of demand? 56. If the Engel curve is upward rising with a negative 33. What is the difference between arc elasticity of demand intercept on the horizontal axis, what will be value and point elasticity of demand? of income elasticity of demand at any point on the 34. What will be the value of own price elasticity of demand curve? for a normal good? 57. If the Engel curve is upward rising passing through the 35. What will be the value of own price elasticity of demand origin, what will be value of income elasticity of demand for a normal necessity good? at any point on the curve? 36. What will be the value of own price elasticity of demand for a normal luxury good?

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MEDIUM-ANSWER TYPE QUESTIONS (4 MARKS) 1. What is law of demand? Why does a demand curve have Table 1.4 Demand schedule of pulses for two negative slope? [CU B Com (G), 2006] consumers 2. Draw and explain separately an individual demand curve and market demand curve for a normal good. Price Quantity Quantity Market per kg. demanded demanded demand [CU B Com (G), 2005, 2012] (`) by consumer by consumer of pulses 3. How is market demand curve determined from an 1 (in kg) 2 (in kg) individual demand curve? 50 1 0 [CU B Com (G), 2005, 2012] 40 2 1 4. The demand schedule of pulses for a consumer is given in 30 3 2 Table 1.3. Derive the individual demand curve for pulses 20 4 3 from the demand schedule. 10 5 4 Table 1.3 Demand schedule of pulses for a consumer 8. Mention two exceptions to the law of demand. Explain Price per kg. (`) Quantity demanded (in kg) the factors affecting demand. [CU B Com (G), 2012] 50 1 9. Distinguish betweenPress ‘change in demand’ and ‘change in 40 2 quantity demanded’. 30 3 10. What do you mean by arc elasticity of demand? How can 20 4 you measure own price elasticity of demand on an arc of 10 5 a straight line demand curve? 11. How can you measure point price elasticity of demand 5. For what reasons does a demand curve shift? Explain on any point of a straight line demand curve? diagrammatically the difference between the change in 12. Prove that on a straight line demand curve, value of point demand and change in quantity demanded? price elasticity of demand will be unity at the mid-point [CU B Com (G), 2007,University 2011] of the demand curve. 6. The demand schedule of pulses for two consumers is 13. Explain the difference between slope of a demand curve given in Table 1.4. Fill up the blanks for market demand and elasticity of demand. in the schedule and derive the market demand curve for 14. Explain the concepts of income elasticity of demand and pulses from the demand schedule assuming that there are cross-price elasticity of demand. [CU B Com (G), 2011] only two consumers in the whole market. 15. Define cross-price elasticity of demand. How are the 7. State the law of demand. MentionOxford two exceptions to this concerned goods related to each other if the cross-price law. Explain the factors affecting demand. elasticity is positive? [CU B Com (G), 2012] [CU B Com (G), 2009] 16. How can you measure income elasticity of demand?

LONG-ANSWER TYPE QUESTIONS (8 MARKS) 1. What is price elasticity of demand? On what factors does 3. Show that on a linear demand curve, the absolute it depend? [CU B Com (G), 2007] value of elasticity of demand varies between zero and 2. What is price elasticity of demand? How can the price infinity. elasticity of demand be measured at a point on a downward 4. What is the relation between slope of a demand curve sloping straight line demand curve? and elasticity of demand? Show that two demand curves [CU B Com (G), 2008] can have same slope but different elasticities of demand

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and two demand curves can have same elasticity of of demand depends on the relation between the demand but different slope. concerned goods. 5. Define the concepts of the following: 7. What do you mean by elasticity of supply? How • Income elasticity of demand can you measure elasticity of supply at any point on • Cross-price elasticity of demand the supply curve? [CU B Com (G), 2009] 8. What do you mean by elastic and inelastic supply? 6. What do you mean by cross-price elasticity of Show how shapes of the supply curve will be demand? Show that the value of cross-price elasticity different for different values of elasticity of supply.

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