Abstract
In the inspection of a lot of products, it occurs rather often that all of the defective items can not be detected for some reason or other. When we re-inspect the items which were once looked on as non-defective, both the probability of overlooking the defective items and the number of defectives in the lot are estimable. In this case the method of maximum likelihood and that of conditional maximum likelihood are shown to be effective if the probability of overlooking is not so large. The effects of variation of the probability upon the estimators are also investigated.
