摘要：We propose a variance estimator based on factor type imputation in the presence of non-response. Properties of the proposed classes of estimators are studied and their optimality conditions are derived. The proposed classes of factor type ratio estimators are shown to be more efficient than some of the existing estimators, namely, the usual unbiased estimator of variance, ratio-type, dual to ratio type and ratio cum dual to ratio estimators. Their performances are assessed on the basis of relative efficiencies. Findings are illustrated based on a simulated and real data set.
关键词：auxiliary information;mean squared error;simple random sampling without replacement (SRSWOR)
