1. Faculty of Policy Management , Keio University , Fujisawa, Kanagawa, 252, Japan;2. Department of Management Information , Junior College of Tokiwa University , Miwa, Mito, 310, Japan
Abstract:
The problem of simultaneous estimation of normal means is considered when variances are unequal and the loss is sum of squared errors. Minimaxity or non-minimaxity of empirical Bayes estimators is investigated when the common prior distribution is given by normal one with mean 0. Minimaxity results for the case when the loss is a weighted sum of squared errors is also given. Monte Carlo simulation results are given to compare the risk behavior of the empirical Bayes estimator with those of other minimax ones.