The Variance of an Estimator with Post-Stratified Weighting

Abstract

A straightforward procedure is presented which uses the variance formula of a simple estimator to obtain an approximate formula for the variance of a post-stratified estimator. The approximation is the well-known one for the variance of a ratio estimator. The technique is applied to samples which have been selected in stratified and multistage designs and can be extended to other ratio estimators.