AHM As a Measure of Central Tendency of Sex Ratio
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Biometrics & Biostatistics International Journal Research Article Open Access AHM as a measure of central tendency of sex ratio Abstract Volume 10 Issue 2 - 2021 In some recent studies, four formulations of average namely Arithmetic-Geometric Mean Dhritikesh Chakrabarty (abbreviated as AGM), Arithmetic-Harmonic Mean (abbreviated as AHM), Geometric- Department of Statistics, Handique Girls’ College, Gauhati Harmonic Mean (abbreviated as GHM) and Arithmetic-Geometric-Harmonic Mean University, India (abbreviated as AGHM) have recently been derived from the three Pythagorean means namely Arithmetic Mean (AM), Geometric Mean (GM) and Harmonic Mean (HM). Each Correspondence: Dhritikesh Chakrabarty, Department of of these four formulations has been found to be a measure of central tendency of data. in Statistics, Handique Girls’ College, Gauhati University, India, addition to the existing measures of central tendency namely AM, GM & HM. This paper Email focuses on the suitability of AHM as a measure of central tendency of numerical data of ratio type along with the evaluation of central tendency of sex ratio namely male-female ratio and female-male ratio of the states in India. Received: May 03, 2021 | Published: May 25, 2021 Keywords: AHM, sex ratio, central tendency, measure Introduction however, involve huge computational tasks. Moreover, these methods may not be able to yield the appropriate value of the parameter if Several research had already been done on developing definitions/ observed data used are of relatively small size (and/or of moderately 1,2 formulations of average, a basic concept used in developing most large size too) In reality, of course, the appropriate value of the 3 of the measures used in analysis of data. Pythagoras is the first parameter is not perfectly attainable in practical situation. What one mathematician to introduce the concept of average and develop its can expect is to obtain that value which is more and more close to formulation. He had developed three formulations/definitions of the appropriate value of the parameter. Four methods have therefore 4,5 average which were later named as Pythagorean means as a mark been developed for determining such value of parameter. These four of honor to him. The three Pythagorean means are Arithmetic Mean methods involve lighter load of computational work than respective (AM), Geometric Mean (GM) & Harmonic Mean (HM). A number of load involved in the earlier methods and can be applied even if the definitions/formulations of average have already been developed in observed data used are of small size.61-64 The methods developed are 6-19 continuation to the three Pythagorean means. The next attempt had based on the concepts of Arithmetic-Geometric Mean (abbreviated as been initiated towards the development of generalized formulation/ AGM),61,62,67,68,69 Arithmetic-Harmonic Mean (abbreviated as AHM),63 20 definition of average. Kolmogorov formulated one generalized Geometric-Harmonic Mean (abbreviated as GHM)64 and Arithmetic- 7,8 definition of average namely Generalized f - Mean. It has been Geometric-Harmonic Mean (abbreviated as AGHM)65,66 respectively. shown that the definitions/formulations of the existing means and also Each of these four formulations namely AGM, AHM, GHM & AGHM 9,10 of some new means can be derived from this Generalized f - Mean. has been found to be a measure of parameter µ of the model described In an study, Chakrabarty formulated one generalized definition by equation (1.1). In other words, each of these four formulations can 11 of average namely Generalized fH – Mean. In another study, be regarded as a measure of the central tendency, in addition to the Chakrabarty formulated another generalized definition of average usual measures of central tendency namely AM, GM & HM of the namely Generalized f – Mean12,13 and developed one general method G observed values xx12, ,........., xN since the values can be expressed 15-17 of defining average as well as the different formulations of average by the model (1.1) if µ is the central tendency of them and vice versa. 19 from the first principles. However, for different types of data different measures are suitable. In many real situations, observed numerical data This paper focuses on the suitability of AHM as a measure of central tendency of numerical data of ratio type along with the evaluation of xx, ,........., x 12 N central tendency of sex ratio namely male-female ratio and female- are found to be composed of some parameter µ and respective male ratio of the states in India. errors Four formulations of average from εε, ,......, ε 12 Z pythagorean means usually of random in nature i.e Let xii = µε+ , (i =1 , 2 , ………… ,N ) (1.1)21-29 xx, ,........., x 12 N The statistical methods of estimation of the parameter developed so far namely least squares estimation, maximum likelihood N positive numbers or values or observations (not all equal or estimation, minimum variance unbiased estimation, method of identical) moment estimation and minimum chi-square estimation,31-52 cannot and provide appropriate value of the parameter µ.21-23 Therefore, some 1 N methods have recently been developed for determining the value of a= AM x, x ,........., x = x , (2.1) 0( 12 Ni) ∑i=1 parameter µ in the situation mentioned above.21-30,53-60 These methods, N Submit Manuscript | http://medcraveonline.com Biom Biostat Int J. 2021;10(2):50‒57. 50 ©2021 Chakrabarty. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially. Copyright: AHM as a measure of central tendency of sex ratio ©2021 Chakrabarty 51 Arithmetic-geometric-harmonic mean (AGHM) N 1/ N g0= GM( x 12, x ,........ ., xNi) =( ∏ =1 xi ) (2.2) /// /// /// /// The three sequences an=1/3( agh n−1 ++ nn −−11), defined respectively −1 1 N by = = −1 & h0 HM( x 12, x ,........., xNi) ∑ = x (2.3) N i 1 /// /// /// /// an=1/3( agh n−1 ++ nn −−11), (2.14) i.e. ag00, & h0 are respectively the Arithmetic Mean (AM), the /// /// ////// 1/3 Geometric Mean (GM) & the Harmonic Mean (HM) of xx12, ,........., xN gn= ( an−11 g nn −− h 1 ) (2.15) which satisfy the inequality [4 , 5] namely −1 /// ///−1 /// −−11 /// & hn= {1/3( an−1 + g nn −− 11 + h )} (2.16) AM > GM > HM i.e. h<< ga (2.4) 0 00 Arithmetic-geometric mean (AGM) converges to a common limit M AGH which can be termed as the Arithmetic-Geometric-Harmonic Mean (abbreviated as AGHM) of The two sequences{agnn} &{ } respectively defined by 65,66 xx12, ,........., xN . 1 Thus, an+1 =( ag nn + ) 2 (2.5) AGHM( xx12, ,........., xN ) = common converging point of 1 = 2 (2.17) & gn+1 ( ag nn ) (2.6) /// /// /// {agnn},&,{ } { h n} where the square root assumes the principal value, converge to a common point M AG which can be termed as the AHM as measure of central tendency of sex Arithmetic-Geometric Mean (abbreviated as AGM) of xx12, ,........., xN ratio [61 , 62, 66 , 67 , 68]. Let Thus, xx12, ,........., xN AGM( xx12, ,........., xN ) = common converging point of be observed values (which are strictly positive and not all identical) {ag} &{ } (2.7) nn on the Ratio Male/Female. Arithmetic-harmonic mean (AHM) Also let µ be the central tendency of the observed values. / // The two sequences an+ 1 =½() ah nn + respectively defined by Then can be expressed as / // x =µε + (3.1) an+ 1 =½() ah nn + ii (2.8) − −− ε / / 1 / 1 1 where i is the error associated to xi for (i = 1 , 2 , ………… , N) & hn+ 1= ½( ah nn + )} (2.9) which is random in nature converge to common point M AH which can be termed as the i.e. each ε assumes either positive real value or negative real Arithmetic-Harmonic Mean (abbreviated as AHM) of xx, ,........., x i 12 N value with equal probability. .63,66 Again since µ is the central tendency of the observed values Thus, xx12, ,........., xN AHM ( xx12, ,........., xN ) = common converging point of // (2.10) − 1 {}{ahnn & } therefore, µ will be the central tendency of reciprocals xx−−11, ,........., x − 1 Geometric-harmonic mean (GHM) 12 N // // of the observed values. The two sequences {g n}{ & h n } defined respectively by Accordingly, the reciprocals can be expressed as 1 // // // 2 −−1 1/ g+ = g. h n1 ( nn) xii=µε + , (I = 1 , 2 , ………… ,N ) (2.11) (3.2) −1 hh// =1 g//−−11 + // where & n+1 { 2( nn)} (2.12) −−11 − 1 xx12, ,........., xN are the random errors, which assume positive and where the square root takes the principal value, negative values in random order, associated to are the random errors associated to converge to common point MGH which can be termed as the −− − Geometric-Harmonic Mean (abbreviated as GHM) of xx, ,........., x 11 1 12 N xx12, ,........., xN respectively. .64,66 Let us now write Thus, GHM( xx12, ,........., xN ) = common converging point of AM( xx12, ,........., xN ) = a0 (3.3) // (2.13) // & HM( xx12, ,........., xN ) = h0 (3.4) {}g}n & {h n Citation: Chakrabarty D. AHM as a measure of central tendency of sex ratio. Biom Biostat Int J. 2021;10(2):50‒57. DOI: 10.15406/bbij.2021.10.00330 Copyright: AHM as a measure of central tendency of sex ratio ©2021 Chakrabarty 52 // and then define the two sequences {}{ahnn & } respectively by which implies, δδnn+1 < since ½(δδnn+<e ) n /= // + / an+ 1 ½ ( ah nn ) (3.5) This implies, h n becomes more and more smaller as n becomes / / −−1 /− 1 1 more and more larger. & hn+ 1 = ½( ah nn + )} (3.6) This means. a/ becomes more and more closer to µ as n becomes // n Then, both of {}{}ahnn & converges to some common real more and more larger.