Economic designs of life test sampling plans for repairable products

Economic designs of life test sampling plans are considered for repairable products which are sold under a general rebate warranty policy. It is assumed that the products in each lot have the same failure intensity function, but the parameters of the function vary from lot to lot according to a known prior distribution. Cost models are constructed which involve three cost components; test cost, accept cost, and reject cost. Methods of finding optimal sampling plans which minimize the expected average cost per lot are presented. Numerical examples are given and sensitivity analyses for parameters of the prior distribution are performed.