Media Diversity and the Analysis of Qualitative Variation
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EART6 Lab Standard Deviation in Probability and Statistics, The
EART6 Lab Standard deviation In probability and statistics, the standard deviation is a measure of the dispersion of a collection of values. It can apply to a probability distribution, a random variable, a population or a data set. The standard deviation is usually denoted with the letter σ. It is defined as the root-mean-square (RMS) deviation of the values from their mean, or as the square root of the variance. Formulated by Galton in the late 1860s, the standard deviation remains the most common measure of statistical dispersion, measuring how widely spread the values in a data set are. If many data points are close to the mean, then the standard deviation is small; if many data points are far from the mean, then the standard deviation is large. If all data values are equal, then the standard deviation is zero. A useful property of standard deviation is that, unlike variance, it is expressed in the same units as the data. 2 (x " x ) ! = # N N Fig. 1 Dark blue is less than one standard deviation from the mean. For Fig. 2. A data set with a mean the normal distribution, this accounts for 68.27 % of the set; while two of 50 (shown in blue) and a standard deviations from the mean (medium and dark blue) account for standard deviation (σ) of 20. 95.45%; three standard deviations (light, medium, and dark blue) account for 99.73%; and four standard deviations account for 99.994%. The two points of the curve which are one standard deviation from the mean are also the inflection points. -
Robust Logistic Regression to Static Geometric Representation of Ratios
Journal of Mathematics and Statistics 5 (3):226-233, 2009 ISSN 1549-3644 © 2009 Science Publications Robust Logistic Regression to Static Geometric Representation of Ratios 1Alireza Bahiraie, 2Noor Akma Ibrahim, 3A.K.M. Azhar and 4Ismail Bin Mohd 1,2 Institute for Mathematical Research, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia 3Graduate School of Management, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia 4Department of Mathematics, Faculty of Science, University Malaysia Terengganu, 21030, Malaysia Abstract: Problem statement: Some methodological problems concerning financial ratios such as non- proportionality, non-asymetricity, non-salacity were solved in this study and we presented a complementary technique for empirical analysis of financial ratios and bankruptcy risk. This new method would be a general methodological guideline associated with financial data and bankruptcy risk. Approach: We proposed the use of a new measure of risk, the Share Risk (SR) measure. We provided evidence of the extent to which changes in values of this index are associated with changes in each axis values and how this may alter our economic interpretation of changes in the patterns and directions. Our simple methodology provided a geometric illustration of the new proposed risk measure and transformation behavior. This study also employed Robust logit method, which extends the logit model by considering outlier. Results: Results showed new SR method obtained better numerical results in compare to common ratios approach. With respect to accuracy results, Logistic and Robust Logistic Regression Analysis illustrated that this new transformation (SR) produced more accurate prediction statistically and can be used as an alternative for common ratios. Additionally, robust logit model outperforms logit model in both approaches and was substantially superior to the logit method in predictions to assess sample forecast performances and regressions. -
Ocr IB 1967 '70
ocr IB 1967 '70 OAK RIDGE NATIONAL LABORATORY operated by UNION CARBIDE CORPORATION NUCLEAR DIVISION for the • U.S. ATOMIC ENERGY COMMISSION ORNL - TM- 1919 INDICES OF QUALITATIVE VARIATION Allen R. Wilcox NOTICE This document contains information of a preliminary natur<> and was prepared primarily far internal use at the Oak Ridge National Laboratory. It is subject to revision or correction and therefore doe> not represent o finol report. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. .-------------------LEGAL NOTICE--------------~ This report was prepared as on account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, compl""t"'n~<~~:oo;, nr ulltf!fulnes!l: of the information conto1ned in this report, or that the use of any information, apparatus, method, or process disc lased in this report may not infringe privately ownsd rights; or B. -
Iam 530 Elements of Probability and Statistics
IAM 530 ELEMENTS OF PROBABILITY AND STATISTICS LECTURE 3-RANDOM VARIABLES VARIABLE • Studying the behavior of random variables, and more importantly functions of random variables is essential for both the theory and practice of statistics. Variable: A characteristic of population or sample that is of interest for us. Random Variable: A function defined on the sample space S that associates a real number with each outcome in S. In other words, a numerical value to each outcome of a particular experiment. • For each element of an experiment’s sample space, the random variable can take on exactly one value TYPES OF RANDOM VARIABLES We will start with univariate random variables. • Discrete Random Variable: A random variable is called discrete if its range consists of a countable (possibly infinite) number of elements. • Continuous Random Variable: A random variable is called continuous if it can take on any value along a continuum (but may be reported “discretely”). In other words, its outcome can be any value in an interval of the real number line. Note: • Random Variables are denoted by upper case letters (X) • Individual outcomes for RV are denoted by lower case letters (x) DISCRETE RANDOM VARIABLES EXAMPLES • A random variable which takes on values in {0,1} is known as a Bernoulli random variable. • Discrete Uniform distribution: 1 P(X x) ; x 1,2,..., N; N 1,2,... N • Throw a fair die. P(X=1)=…=P(X=6)=1/6 DISCRETE RANDOM VARIABLES • Probability Distribution: Table, Graph, or Formula that describes values a random variable can take on, and its corresponding probability (discrete random variable) or density (continuous random variable). -
Current Practices in Quantitative Literacy © 2006 by the Mathematical Association of America (Incorporated)
Current Practices in Quantitative Literacy © 2006 by The Mathematical Association of America (Incorporated) Library of Congress Catalog Card Number 2005937262 Print edition ISBN: 978-0-88385-180-7 Electronic edition ISBN: 978-0-88385-978-0 Printed in the United States of America Current Printing (last digit): 10 9 8 7 6 5 4 3 2 1 Current Practices in Quantitative Literacy edited by Rick Gillman Valparaiso University Published and Distributed by The Mathematical Association of America The MAA Notes Series, started in 1982, addresses a broad range of topics and themes of interest to all who are in- volved with undergraduate mathematics. The volumes in this series are readable, informative, and useful, and help the mathematical community keep up with developments of importance to mathematics. Council on Publications Roger Nelsen, Chair Notes Editorial Board Sr. Barbara E. Reynolds, Editor Stephen B Maurer, Editor-Elect Paul E. Fishback, Associate Editor Jack Bookman Annalisa Crannell Rosalie Dance William E. Fenton Michael K. May Mark Parker Susan F. Pustejovsky Sharon C. Ross David J. Sprows Andrius Tamulis MAA Notes 14. Mathematical Writing, by Donald E. Knuth, Tracy Larrabee, and Paul M. Roberts. 16. Using Writing to Teach Mathematics, Andrew Sterrett, Editor. 17. Priming the Calculus Pump: Innovations and Resources, Committee on Calculus Reform and the First Two Years, a subcomit- tee of the Committee on the Undergraduate Program in Mathematics, Thomas W. Tucker, Editor. 18. Models for Undergraduate Research in Mathematics, Lester Senechal, Editor. 19. Visualization in Teaching and Learning Mathematics, Committee on Computers in Mathematics Education, Steve Cunningham and Walter S. -
Measurements of Entropic Uncertainty Relations in Neutron Optics
applied sciences Review Measurements of Entropic Uncertainty Relations in Neutron Optics Bülent Demirel 1,† , Stephan Sponar 2,*,† and Yuji Hasegawa 2,3 1 Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany; [email protected] 2 Atominstitut, Vienna University of Technology, A-1020 Vienna, Austria; [email protected] or [email protected] 3 Division of Applied Physics, Hokkaido University Kita-ku, Sapporo 060-8628, Japan * Correspondence: [email protected] † These authors contributed equally to this work. Received: 30 December 2019; Accepted: 4 February 2020; Published: 6 February 2020 Abstract: The emergence of the uncertainty principle has celebrated its 90th anniversary recently. For this occasion, the latest experimental results of uncertainty relations quantified in terms of Shannon entropies are presented, concentrating only on outcomes in neutron optics. The focus is on the type of measurement uncertainties that describe the inability to obtain the respective individual results from joint measurement statistics. For this purpose, the neutron spin of two non-commuting directions is analyzed. Two sub-categories of measurement uncertainty relations are considered: noise–noise and noise–disturbance uncertainty relations. In the first case, it will be shown that the lowest boundary can be obtained and the uncertainty relations be saturated by implementing a simple positive operator-valued measure (POVM). For the second category, an analysis for projective measurements is made and error correction procedures are presented. Keywords: uncertainty relation; joint measurability; quantum information theory; Shannon entropy; noise and disturbance; foundations of quantum measurement; neutron optics 1. Introduction According to quantum mechanics, any single observable or a set of compatible observables can be measured with arbitrary accuracy. -
THE USE of EFFECT SIZES in CREDIT RATING MODELS By
THE USE OF EFFECT SIZES IN CREDIT RATING MODELS by HENDRIK STEFANUS STEYN submitted in accordance with the requirements for the degree of MASTER OF SCIENCE in the subject STATISTICS at the UNIVERSITY OF SOUTH AFRICA SUPERVISOR: PROF P NDLOVU DECEMBER 2014 © University of South Africa 2015 Abstract The aim of this thesis was to investigate the use of effect sizes to report the results of statistical credit rating models in a more practical way. Rating systems in the form of statistical probability models like logistic regression models are used to forecast the behaviour of clients and guide business in rating clients as “high” or “low” risk borrowers. Therefore, model results were reported in terms of statistical significance as well as business language (practical significance), which business experts can understand and interpret. In this thesis, statistical results were expressed as effect sizes like Cohen‟s d that puts the results into standardised and measurable units, which can be reported practically. These effect sizes indicated strength of correlations between variables, contribution of variables to the odds of defaulting, the overall goodness-of-fit of the models and the models‟ discriminating ability between high and low risk customers. Key Terms Practical significance; Logistic regression; Cohen‟s d; Probability of default; Effect size; Goodness-of-fit; Odds ratio; Area under the curve; Multi-collinearity; Basel II © University of South Africa 2015 i Contents Abstract .................................................................................................................................................. -
Measures of Central Tendency (Mean, Mode, Median,) Mean • Mean Is the Most Commonly Used Measure of Central Tendency
Measures of Central Tendency (Mean, Mode, Median,) Mean • Mean is the most commonly used measure of central tendency. • There are different types of mean, viz. arithmetic mean, weighted mean, geometric mean (GM) and harmonic mean (HM). • If mentioned without an adjective (as mean), it generally refers to the arithmetic mean. Arithmetic mean • Arithmetic mean (or, simply, “mean”) is nothing but the average. It is computed by adding all the values in the data set divided by the number of observations in it. If we have the raw data, mean is given by the formula • Where, ∑ (the uppercase Greek letter sigma), refers to summation, X refers to the individual value and n is the number of observations in the sample (sample size). • The research articles published in journals do not provide raw data and, in such a situation, the readers can compute the mean by calculating it from the frequency distribution. Mean contd. • Where, f is the frequency and X is the midpoint of the class interval and n is the number of observations. • The standard statistical notations (in relation to measures of central tendency). • The mean calculated from the frequency distribution is not exactly the same as that calculated from the raw data. • It approaches the mean calculated from the raw data as the number of intervals increase Mean contd. • It is closely related to standard deviation, the most common measure of dispersion. • The important disadvantage of mean is that it is sensitive to extreme values/outliers, especially when the sample size is small. • Therefore, it is not an appropriate measure of central tendency for skewed distribution. -
Introduction
DA-STATS Introduction Shan E Ahmed Raza Department of Computer Science University of Warwick [email protected] DASTATS – Teaching Team Shan E Ahmed Raza Fayyaz Minhas Richard Kirk Introduction 2 About Me • PhD (Computer Science) University of Warwick 2011-2014 warwick.ac.uk/searaza Supervisor(s): Professor Nasir Rajpoot and Dr John Clarkson • Research Fellow University of Warwick 2014 – 2017 • Postdoctoral Fellow The Institute of Cancer Research 2017 – 2019 • Assistant Professor Computer Science, University of Warwick 2019 • Research Interests Computational Pathology Multi-Channel and Multi-Model Image Analysis Deep Learning and Pattern Recognition Introduction 3 Course Outline • Introduction To Descriptive And Predictive Techniques. warwick.ac.uk/searaza • Introduction To Python. • Data Visualisation And Reporting Techniques. • Probability And Bayes Theorem • Sampling From Univariate Distributions. • Concepts Of Multivariate Analysis. • Linear Regression. • Application Of Data Analysis Requirements In Work. • Appreciate Of Limitations Of Traditional Analysis. Introduction 4 DA-STATS Topic 01: Introduction to Descriptive and Predictive Analysis Shan E Ahmed Raza Department of Computer Science University of Warwick [email protected] Outline • Introduction to Descriptive, Predictive and Prescriptive Techniques • Data and Model Driven Modelling • Descriptive Analysis Scales of Measurement and data Measures of central tendency, statistical dispersion and shape of distribution • Correlation Techniques DA-STATS - Topic 01: Introduction -
Measuring Variation for Nominal Data
Bulletin ofthe Psychonomic Society 1988. 26 (5), 433-436 Measuring variation for nominal data TARALD O. KVALSETH University of Minnesota , Minneapolis, Minnesota This paper is concerned with the measurement of variation or dispersion for nominal categori cal data. A new measure of such variation is proposed. It is defined as the complement of the standard deviation of the individual category frequencies from the modal frequency. Large-sample distribution methods are developed for constructing confidence intervals and testing hypotheses for the equivalent population measure of variation. Numerical sample data are used to exem plify the statistical inference methods. For measuring the variation or dispersion in a set of measures, the IQV in Equation 2 appears to be the most nominal data, a number ofalternative measures have been widely accepted, especially in the social sciences (e.g., defined in the literature. Such measures are generally Ott, Mendenhall, & Larson, 1978, pp. 110-113). The functions ofthe absolute frequencies or counts nh n2, . .. , measure in Equation 3, which is based on Shannon's n, for a set of I categories that are exhaustive and mutu (1948) entropy in information theory, has been used quite ally exclusive. Thus, among the total number ofn = Elnl extensively in the biological sciences (Pielou, 1977). observations (individuals or items), n, observations be The measure MOM in Equation 1 suffers from one seri long to category i, with each observation belonging to one ous limitation: its value is determined exclusively by the and only one category. Among the best known variation relative modal frequency nm/n and I (the number of measures for the n, (i = 1, 2, . -
KOF Working Papers, No
A Service of Leibniz-Informationszentrum econstor Wirtschaft Leibniz Information Centre Make Your Publications Visible. zbw for Economics Maag, Thomas Working Paper On the accuracy of the probability method for quantifying beliefs about inflation KOF Working Papers, No. 230 Provided in Cooperation with: KOF Swiss Economic Institute, ETH Zurich Suggested Citation: Maag, Thomas (2009) : On the accuracy of the probability method for quantifying beliefs about inflation, KOF Working Papers, No. 230, ETH Zurich, KOF Swiss Economic Institute, Zurich, http://dx.doi.org/10.3929/ethz-a-005859391 This Version is available at: http://hdl.handle.net/10419/50407 Standard-Nutzungsbedingungen: Terms of use: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Documents in EconStor may be saved and copied for your Zwecken und zum Privatgebrauch gespeichert und kopiert werden. personal and scholarly purposes. Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle You are not to copy documents for public or commercial Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich purposes, to exhibit the documents publicly, to make them machen, vertreiben oder anderweitig nutzen. publicly available on the internet, or to distribute or otherwise use the documents in public. Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, If the documents have been made available under an Open gelten abweichend von diesen Nutzungsbedingungen die in der dort Content Licence (especially Creative Commons Licences), you genannten Lizenz gewährten Nutzungsrechte. may exercise further usage rights as specified in the indicated licence. www.econstor.eu KOF Working Papers On the Accuracy of the Probability Method for Quantifying Beliefs about Inflation Thomas Maag No. -
The Need to Measure Variance in Experiential Learning and a New Statistic to Do So
Developments in Business Simulation & Experiential Learning, Volume 26, 1999 THE NEED TO MEASURE VARIANCE IN EXPERIENTIAL LEARNING AND A NEW STATISTIC TO DO SO John R. Dickinson, University of Windsor James W. Gentry, University of Nebraska-Lincoln ABSTRACT concern should be given to the learning process rather than performance outcomes. The measurement of variation of qualitative or categorical variables serves a variety of essential We contend that insight into process can be gained purposes in simulation gaming: de- via examination of within-student and across-student scribing/summarizing participants’ decisions for variance in decision-making. For example, if the evaluation and feedback, describing/summarizing role of an experiential exercise is to foster trial-and- simulation results toward the same ends, and error learning, the variance in a student’s decisions explaining variation for basic research purposes. will be greatest when the trial-and-error stage is at Extant measures of dispersion are not well known. its peak. To the extent that the exercise works as Too, simulation gaming situations are peculiar in intended, greater variances would be expected early that the total number of observations available-- in the game play as opposed to later, barring the usually the number of decision periods or the game world encountering a discontinuity. number of participants--is often small. Each extant measure of dispersion has its own limitations. On the other hand, it is possible that decisions may Common limitations are that, under ordinary be more consistent early and then more variable later circumstances and especially with small numbers if the student is trying to recover from early of observations, a measure may not be defined and missteps.