Estimating the Proportion of Immunes in a Censored Sample
提出一个估计总体中免疫者比例的估计量，基于Kaplan-Meier经验分布函数的最大观测值，证明其一致性和渐近正态性，并通过模拟验证小样本下的近似正态性。
An estimator for the proportion of ‘immunes’ in a population is proposed, when a sample of censored failure times is available. Our suggestion is to use one minus the maximum observed value of the Kaplan-Meier empirical distribution function. This estimator is shown to be consistent and asymptotically normal, under modest conditions on the censoring mechanism. Simulations suggest that the estimator is approximately normal for quite small sample sizes, provided the immune proportion is not too close to zero. A simple nonparametric statistic is proposed to test whether the assumptions of the analysis are likely to be valid.