Life Test Based on Progressively Group-Censored Samples From Exponential Distribution With Periodic Change in Failure Rate

A life test experiment based on progressively group censored sample with periodic change in the failure rate of an exponential distribution is considered. Estimates of the two failure rates under different conditions of usage of an item together with their asymptotic standard error are obtained by the method of maximum likelihood. A numerical example is given using the data available in the form of grouped observations under two conditions of usage during alternate time intervals of fixed lengths T/Sub1 and T/Sub2