RATIO-PRODUCT-DIFFERENCE (RPD) TYPE DOUBLE SAMPLING ESTIMATORS FOR FINITE POPULATION VARIANCE USING AUXILIARY INFORMATION
For estimating finite population variance using information on single auxiliary variable in the form of mean, the Ratio-Product-Difference (RPD) type double sampling estimators d1 and d2 and their generalized estimators as d1g and d2g are proposed. The bias and mean square error (MSE) of the proposed estimators are found. Theoretical comparisons with the traditional estimator are carried out. By this comparison it is shown that the proposed estimators are more efficient than the traditional one.