THE EXACT ANALYSIS OF SEQUENTIAL LIFE TESTS WITH PARTICULAR APPLICATION TO AGREE PLANS

In this paper we give methods for the exact analysis of any sequential life test, under the assumption that the underlying distribution of times to failure or times between failure is exponential. The procedure is recursive in nature and can be carried out easily with a modern high-speed computer. The work was stimulated by a desire to study the effect of truncation in sequential life tests and in particular to compute exactly the properties of the life test plans recommended in the AGREE (Advisory Group on the Reliability of Electronic Equipment) report. Roughly speaking, the AGREE plans are obtained by superimposing a truncated test of the type studied by Epstein¹ on the sequential life test given by Epstein and Sobel². The results of these computations are given in detail in the Appendix.