We study the life distribution of an operating device through the notion of mean residual life. The device is experiencing a random number of shocks governed by a homogeneous Poisson process, and a new U-statistic test procedure is introduced to test the hypothesis of that the life is...

Nonparametric procedures are proposed for testing exponentiality against several new aging classes of life distributions. The main idea is to test if the lifetime of a system, whose failure time has occurred in between visits, belongs to some alternative new aging classes of life distribution....