Robust Improvement in Estimation of a Covariance Matrix in an Elliptically Contoured Distribution Respect to Quadratic Loss Function

Authors

  • Zahra Khodadadi
  • Bahram Tarami

DOI:

https://doi.org/10.30495/jme.v0i0.36

Keywords:

Covariance matrix, elliptically con- toured distribution, expected value, multivariate linear model, squared loss.

Abstract

Let S be matrix of residual sum of square in linear model Y = A¯ + e where matrix e is distributed as elliptically contoured with unknown scale matrix §. In present work, we con- sider the problem of estimating § with respect to squared loss function, L(^§;§) = tr( ^§§¡1¡I)2. It is shown that improvement of the estimators were obtained by James, Stein [7], Dey and Sri- vasan [1] under the normality assumption remains robust under an elliptically contoured distribution respect to squared loss function.

Author Biographies

Zahra Khodadadi

Department of Statistics Islamic Azad University Science Research Branch, Tehran Tehran, Iran

Bahram Tarami

Department of Mathematics College of Sciences Yasouj University Yasouj, Iran.

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Published

2008-03-01

Issue

Section

Vol. 3, No. 1 (2008)