熵损失下协方差矩阵最佳仿射同变估计的改进

Improvement on the Best Affine Equivariant Estimation of the Covariance Matrix under the Entropy Loss

  • 摘要:X1,…, Xnnp)是来自多元正态分布Npμ, ∑)的一个样本,其中μRP ,∑>0均未知.本文在熵损失 L(\widehat\Sigma, \Sigma)=\operatornametr\left(\Sigma^-1 \widehat\Sigma\right)-\log \left|\Sigma^-1 \widehat\Sigma\right|-p下证明了协方差矩阵∑的最佳仿射同变估计是不容许的,且给出了其改进估计。

     

    Abstract: Let X1,…, Xnnp) be a random sample from multivariate normal distribution Npμ, ∑), where μRP and ∑ is a positive definite matrix, both μ and ∑ being unknown. In this paper it is shown for the entropy loss L(\widehat\Sigma, \Sigma)=\operatornametr\left(\Sigma^-1 \widehat\Sigma\right)-\log \left|\Sigma^-1 \widehat\Sigma\right|-p the best affine equivariant estimator of the covariance matrix ∑ is inadmissible and an improved estimator is explicitly constructed.

     

/

返回文章
返回