A GENERALIZED CLASS RATIO-TYPE ESTIMATOR OF POPULATION MEAN BASED ON POST STRATIFICATION AND SUB-SAMPLING OF NON– RESPONDENTS

A A SODIPO

Abstract


Several authors have considered estimators aimed at reducing the bias due to nonresponse  in the estimation of the population mean, of a study variable y. Hansen and Hurwiz (1946) suggested a simple unbiased estimator y , in their attempt to reduce the nonresponse bias present in a survey. Similarly, Rao (1986) proposed an unbiased estimator yps  for practical situations that do frequently arise whereby one considers it desirable to make use of an auxiliary variable x (with full response) in post-stratifying the nonrespondents, even though its population mean X,  as well as the sampling frame within each stratum are both unknown, and the strata weight          Wh(h=,….,L)obsolete.  Sodipo (1998) developed the work of Rao (1986) by constructing a ratio-type estimator  g1, which was shown to be more efficient. In this present study, we propose a class ratio-type estimator g2, which is proved (theoretically and empirically) to be more efficient than, and also contains, the last two of the three existing estimators mentioned earlier. Expression for the optimum values of n and kh(h=2…,L) are also derived, using a relevant cost function.

 

 

 


Keywords


Mean, estimator, post-stratification, auxiliary variable, nonresponse.

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