Simplified Unbiased Variance Estimation for Multistage Designs
多阶段抽样设计中简化的无偏方差估计
All unequal probability selection methods of two first-stage units per stratum are shown to permit the use of a grouping device, leading to simplified unbiased variance estimators in multistage sampling. These variance estimators avoid the calculation of within first-stage components with a high probability. Several desirable properties of the grouping method are established. Empirical results on efficiencies of ‘grouping’ estimators and stabilities of corresponding variance…