Abstract
Life-testing experiments are necessary to guarantee reliability of new products. In life-testing experiments, two cases occur frequently depending on whether or not the failure time is exactly observable during the experimental period. When the exact failure time of a test piece is unknown, we only know that it has failed before the pre-specified inspection time, or it has been still functioning on that time. That is, binary data are observed. Many authors have investigated the optimal designs based on binary data, but they specified one of the design variables before hand out of "number of the different inspection point," "number of samples which are inspected for each point," and "the inspection points," even for the cases with known parameters. This paper deals with the optimization considering the above three factors simultaneously. As a result, for common eight lifetime distributions, the optimal one is given by the design that the number of the inspection time is two and the numbers of the inspected samples are equal for each points.
