摘要：This pap er suggests a class of estimators for population mean of a study variable using known p opulation proportion of an auxiliary character (attribute) which is highly cor- related with the study variable. The suggested class of estimators is more general and includes the usual unbiased estimator (sample mean) and the estimators reported by Singh et al. (2007). Expressions of bias and mean square error (MSE) for the proposed class of estimators have been obtained under large sample approximation. Asymptotic optimum estimator (AOE) has been identified along with its mean square error formula. Regions of preferences have b een investigated under which the proposed class of estima- tors is more e.cient than the usual unbiased, Naik and Gupta (1996) and Singh et al. (2007) estimators. Two phase sampling version (i.e. population proportion is unknown) of the proposed class of estimators has been given along with its properties under large sample approximation. The theoretical results have been illustrated empirically by using some population data sets in both phases.
关键词：Bias ; Mean square error ; Proportion ; Study variable ; Two phase ; sampling.
