Analysis of Hybrid Life-tests in Presence of Competing Risks

The mixture of Type-I and Type-II censoring schemes, called the hybrid censoring scheme is quite common in life-testing or reliability experiments. In this paper, we consider the competing risks model in presence of hybrid censored data. Under this set up, it is assumed that the item may fail due to various causes and the correspond-ing lifetime distributions are independent and exponentially distributed with di®erent scale parameters. We obtain the maximum likelihood estimators of the mean life of the di®erent causes and derive their exact distributions. Using the exact distributions, all the moments can be obtained. Asymptotic con¯dence intervals and two bootstrap con¯dence intervals are also proposed. Bayes estimates and credible intervals of the un-known parameters are obtained under the assumptions of independent inverted gamma priors of the mean life of the di®erent causes. Di®erent methods have been compared using Monte Carlo simulations. One real data set has been analyzed for illustrative purposes