DESINGING DSP (0, 1) ACCEPTANCE SAMPLING PLANS BASED ON TRUNCATED LIFE TESTS UNDER VARIOUS DISTRIBUTIONS USING MINIMUM ANGLE METHOD

Abstract

In this paper DSP (0, 1) sampling plans for truncat ed life tests are developed using minimum angle met hod, when the life time of the items follows some selected distributions. The desi gn parameters of the sampling plan are determined f or pre-determined acceptance number by satisfying two risks at the specified qua lity levels simultaneously. The tables of design pa rameters are provided for various test termination time and mean ratio for some selec ted distributions. The operating characteristic val ues are also provided in the table. Some comparisons are made among the selected distributions. The results are explained with exam ples. Acceptance sampling is a inspecting procedure appli ed in statistical quality control. Acceptance sampling is a part of operations management and service quality maintenance. It is important for industrial, but also for business pur poses helping the decision - making process for the purpose of qu ality management. In a time- truncated sampling plan, a random sample is selected from a lot of products and put o n the test where the number of failures is recorded until the pre - specified time. If the number of failures observed is not greater than the specified acceptance number, then the lot will be accepted. Two risks are always attached to an ac ceptance sampling. The probability of rejecting the good lot is known as the type - 1 error (producer's risk) and it is deno ted by α. The probability of accepting the bad lot is known as th e type - 2 error (consumer's risk) and it is denoted by β. An acceptance sampling plan should be designed so that both risks are smaller than the required values. An acceptance sam pling plan involves quality contracting on product orders betw een the producer's risk and consumer's risk. In many pract ical situations, an important quality characteristic is the lifetime of the product that is, the time over which it fulfill s its task. Sampling plans to determine acceptability of a prod uct based on the number of failures recorded until the pre-sp ecified time are called time-truncated sampling plans.