On the generalized noncentral chi-squared distribution induced by an elliptical gamma law

Abstract

Certain important statistical inference and classification problems lead to the consideration of quadratic forms in rotationally invariant random variables. In this paper noncentral probabilities under a multivariate elliptical gamma distribution are studied. The density and cumulative distribution function of the squared noncentral radii are expressed in a Laguerre series form and certain recurrences are derived. Finally, two numerical approximations are discussed.