Estimation of the precision matrix of multivariate Kotz type model

Abstract

In this paper, the problem of estimating the precision matrix of a multivariate Kotz type model is considered. First, using the quadratic loss function, we prove that the unbiased estimator , where denotes the sample sum of product matrix, is dominated by a better constant multiple of , denoted by . Secondly, a new class of shrinkage estimators of is proposed. Moreover, the risk functions of , and the proposed estimators are explicitly derived. It is shown that the proposed estimator dominates , under the quadratic loss function. A simulation study is carried out which confirms these results. Improved estimator of is also obtained.primary, 62H12 secondary, 62C15 Multivariate Kotz type model Estimation of the precision matrix Quadratic loss Decision theoretic estimation