Improved Estimation of Current Population Mean Over Two Occasions

This paper addresses the role of two auxiliary variables on both the occasions to improve the precision of estimates at current (second) occasion in two occasion successive sampling .Utilizing the readily available information on two auxiliary variables on both the occasions and information on the study variable from the previous occasion, an efficient estimation procedure of population mean on current (second) occasion has been envisaged. It is to be mentioned that out of the two auxiliary variables one auxiliary variable is positively correlated with the study variable while other is negatively correlated. Behavior of the proposed estimator has been studied and compared with the sample mean estimator, when there is no matching from the previous occasion and traditional successive sampling estimator, which is a linear combination of the means of the matched and unmatched portions of the sample at the current (second) occasion. Optimal replacement policy is also discussed. In addition, we support the theoretical results with the aid of numerical examples.

Sri Lankan Journal of Applied Statistics 2015;16(1):1-19