Weibull mixtures have been used extensively in reliability and survival analysis, and they have also been generalized by allowing negative mixing weights, which arise naturally under the formation of some structures of reliability systems. These models provide flexible distributions for modeling...

Weibull mixtures have been widely used in many applications, and they can be generalized by allowing negative mixing weights. In this note, we investigate constraints on the mixing weights and parameters of components under which the generalized mixture of Weibull distributions is a valid...

A new class of bivariate distributions (NBD) was recently introduced by Sarhan and Balakrishnan [A.M. Sarhan, N. Balakrishnan, A new class of bivariate distributions and its mixture, J. Multivariate Anal. 98 (2007) 1508-1527]. In this note, we give the joint survival function of a multivariate...