Prediction in exponential life testing

Let x 1 , x 2 ,…, x r represent the first r failures among n items being life tested. It is of interest to estimate the future failure times and thereby acquire an overall idea of the total test time. Prediction of x s (s>r) was studied by Lawless [4], An improved procedure is developed here based on a different statistic. Special cases of s = r + l and s = n are treated. Illustrative examples are given. A comparison in savings is made with the above method.