Probability Limits on Outgoing Quality for Continuous Sampling Plans

Abstract

We investigate the performance of Dodge's continuous sampling plan 1 (CSP-1) when production run lengths are short or moderate or when the input process is not iid Bernoulli. For finite run lengths. methods are presented for computing upper and lower percentage points (probability limits) for the distributions of the outgoing quality and fraction inspected when the input process is Markov. Both rectifying and nonrectifying inspection are considered. Particular attention is paid to the special case of iid Bernoulli input. Comparisons are made with long-run maximum averages under various input process assumptions, including Dodge's average outgoing quality limit (AOQL) for the iid case, an AOQL for Markov input, and unrestricted AOQL values, These limits arc proposed as new performance measures. intended to supplement the tables in MIL-STD-1235B for use in selecting CSP-1 plans. We also discuss the problem of interval estimation of the incoming and outgoing quality from CSP-1 inspection data.

KEY WORDS:

• Average outgoing quality
• CSP-1
• Estimation
• Inspection by attributes
• Markov chain
• Markov dependent production process
• MIL-STD-1235B