Surya K. Pal

Improved ratio-type estimators of finite population variance using quartiles

In this paper we have proposed some ratio-type estimators of finite population variance using known values of parameters related to an auxiliary variable such as quartiles with their properties in simple random sampling. The suggested estimators have been compared with the usual unbiased and ratio estimators and the estimators due to [2], [12, 13, 14] and [3]. An empirical study is also carried out to judge the merits of the proposed estimator over other existing estimators of population variance using natural data set. 2000 AMS Classification: 62D05

Estimation of population variance using known coefficient of variation of an auxiliary variable in sample surveys

Abstract This paper addresses the problem of estimating the population variance of the study variable y using information on coefficient of variation Cx of an auxiliary variable x. We have suggested a class of estimators for the population variance. Expressions of bias and mean squared error of the proposed class of estimators are obtained under large sample approximation. It is identified that the usual unbiased estimator and Das and Tripathi’s (1978) estimators are members of the suggested class of estimators. It has been shown that proposed class of estimators is more efficient than usual unbiased estimator and Das and Tripathi’s (1978) estimators. An empirical study is given in support of the present study.

An efficient class of estimators of finite population variance using quartiles

ABSTRACT In this paper, we have proposed a class of estimators of finite population variance using known values of parameters related to an auxiliary variable such as quartiles and its properties are studied in simple random sampling. The suggested class of ratio-type estimators has been compared with the usual unbiased, ratio estimators and the class of ratio-type estimators due to Singh et al. [Improved estimation of finite population variance using quartiles, Istatistik – J. Turkish Stat. Assoc. 6(3) (2013), pp. 166–121] and Solanki et al. [Improved ratio-type estimators of finite population variance using quartiles, Hacettepe J. Math. Stat. 44(3) (2015), pp. 747–754]. An empirical study is also carried out to judge the merits of the proposed estimator over other existing estimators of population variance using natural data set. It is found that the proposed class of ratio-type estimators ‘’ is superior to the usual unbiased estimator and the estimators recently proposed by Singh et al. [Improved estimation of finite population variance using quartiles, Istatistik – J. Turkish Stat. Assoc. 6(3) (2013), pp. 166–121] and Solanki et al. [Improved ratio-type estimators of finite population variance using quartiles, Hacettepe J. Math. Stat. 44(3) (2015), pp. 747–754].

Use of several auxiliary variables in estimating the population mean in a two-occasion rotation pattern

ABSTRACT This paper addresses the problem of estimation of the population mean on the current (second) occasion in two-occasion successive sampling. Utilizing the readily available information on several auxiliary variables on both occasions and the information on the study variable from the previous occasion, an estimation procedure of the population mean on the current occasion has been proposed. Theoretical properties of the proposed estimator have been investigated. Optimum replacement policy to the proposed estimator has been discussed. The proposed estimator has been compared empirically with the sample mean estimator, when there is no matching and the optimum estimator which is a linear combination of the means of the matched and unmatched portions of the sample at the current occasion. Appropriate recommendations have been made for practical applications.

An efficient effective rotation pattern in successive sampling over two occasions

ABSTRACT This paper addresses the problem of estimating the population mean on the current occasion in two occasion successive sampling. Based on all the readily available information from first and second occasions, a class of estimators is proposed with its properties. It is identified that the estimator recently suggested by Singh and Homa (Journal of Statistical Theory and Practice, 7: 1, 146–155, 2013) is a member of the suggested class of estimators. The correct expression of the mean squared error/variance of the Singh and Homa (2013) estimator is given. The superiority of the suggested class of estimators is discussed with the sample mean estimator when there is no matching, the best combined estimator given in Cochran (1977, p.346) and Singh and Homa (2013) estimator. Optimum replacement policy has been discussed. Numerical illustration is given in support of the present study.

Estimation of population mean in presence of random non-response

Abstract In the present investigation, an attempt was made to develop some ratio-cum- product type exponential estimators for population mean in case of random non-response in three different situations (i) non-response is present on both the study variate as well as auxiliary variates and population mean of the auxiliary variates are known, (ii) non-response is present only on the study variate and population mean of the auxiliary variates are known and (iii) non-response is present on both the study as well as auxiliary variates but population mean of auxiliary variate is unknown. The biases and mean squared errors of the suggested estimators have been obtained in all three situations. The suggested estimators have been compared with the estimators present in literatures in case of random non-response in all three aforesaid situations. An empirical study has been carried out to support the performance of the suggested estimators obtained theoretically.

A family of efficient estimators of the finite population mean in simple random sampling

ABSTRACT In this paper an estimator of the finite population mean using auxiliary information in sample surveys has been proposed. The bias and mean squared error are obtained under large sample approximation. It has been shown that the proposed estimator performs better than some recently published estimators.

A study on the chain ratio-ratio-type exponential estimator for finite population variance

ABSTRACT This paper considers the problem of estimating the population variance S2y of the study variable y using the auxiliary information in sample surveys. We have suggested the (i) chain ratio-type estimator (on the lines of Kadilar and Cingi (2003)), (ii) chain ratio-ratio-type exponential estimator and their generalized version [on the lines of Singh and Pal (2015)] and studied their properties under large sample approximation. Conditions are obtained under which the proposed estimators are more efficient than usual unbiased estimator s2y and Isaki (1893) ratio estimator. Improved version of the suggested class of estimators is also given along with its properties. An empirical study is carried out in support of the present study.

Improved estimator of population total in PPS sampling

ABSTRACT In this paper, we have considered an estimation of the population total Y of the study variable y, making use of information on an auxiliary variable x. A class of estimators for the population total Y using transformation on both the variables study as well as auxiliary has been suggested based on the probability proportional to size with replacement (PPSWR). In addition to many the usual PPS estimator, Reddy and Raos (1977) estimator and Srivenkataramana and Tracys (1979, 1984, 1986) estimators are shown to be members of the proposed class of estimators. The variance of the proposed class of estimators has been obtained. In particular, the properties of 75 estimators based on different known population parameters of the study as well as auxiliary variables have been derived from the proposed class of estimators. In support of the present study, numerical illustrations are given.

Estimation of finite population mean using auxiliary information in presence of non-response

ABSTRACT This article considers the problem of estimating the finite population mean of the study variable y using information on an auxiliary variable x in presence of non-response. We have suggested two-parameter ratio-product-ratio estimator in two different situations and their properties are studied under large sample approximation. We have presented comparisons of the proposed two-parameter ratio-product-ratio estimator with usual unbiased estimator and ratio estimators (tR1,tR2). An empirical study is carried out in support of the present study.