Estimation of the precision matrix of multivariate Kotz type model

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.