Norell L, Arnason T, Hugason K
Department of Mathematics, University of Uppsala, Sweden.
Biometrics. 1991 Mar;47(1):205-21.
Multistage selection with fixed proportions and selection indices based on covariates of the target variable is studied. Assuming a multivariate normal distribution before the selection, expressions are presented for the expectation and the variance of the target variable in the retained subpopulation. As the numerical evaluation for finite populations requires lengthy computations, some approximations using methods for infinite populations are proposed. Numerical illustrations are given for selections in up to three stages.
研究了基于目标变量协变量的固定比例多阶段选择和选择指数。假设选择前为多元正态分布，给出了保留子总体中目标变量的期望和方差的表达式。由于有限总体的数值评估需要冗长的计算，因此提出了一些使用无限总体方法的近似方法。给出了多达三个阶段选择的数值示例。
