Abstract
In a general linear regression model, a generalized least squares estimator (GLSE) is widely employed as an estimator of regression coefficient. The efficiency of the GLSE is usually measured by its covariance (or risk) matrix. In this paper, it is shown that the covariance matrix remains the same as long as the distribution of the error term is elliptically symmetric. This implies that every efficiency result obtained under normal distribution assumption is still valid under elliptical symmetry. An application to a heteroscedastic linear model is also illustrated.
Similar content being viewed by others
References
Fang KT, Kotz S, Ng KW (1990) Symmetric multivariate and related distributions. Chapman and Hall, London
Kariya T, Kurata H (2004) Generalized least squares. Wiley, London
Kariya T, Toyooka Y (1985) Nonlinear versions of the Gauss–Markov theorem and GLSE. In: Krishnaiah PR (ed) Multivariate analysis, vol VI, pp 345–354
Kubokawa T (1998) Double shrinkage estimation of common coefficients in two regression equations with heteroscedasticity. J Multiv Anal 67: 169–189
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kurata, H. A theorem on the covariance matrix of a generalized least squares estimator under an elliptically symmetric error. Stat Papers 51, 389–395 (2010). https://doi.org/10.1007/s00362-009-0199-7
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00362-009-0199-7
Keywords
- Linear regression model
- Covariance matrix
- Elliptically symmetric distribution
- Generalized least squares estimator
- Heteroscedastic model