An alternative decision rule for quality control in sequential sampling plans

Abstract

The conventional rule for acceptance sampling based on sequential samples is based on the rationale of hypothesis testing developed by Wald (1947). This type of decision rule tests the hypothesis of P=p₁ versus P=p₂ as a proxy for determining whether P>d or P<d with P₁<d<p₂. It requires a zone of indifference between the rejection and acceptance levels p₂ and p₁. In this note, we propose an alternative rule for making the decision based on the confidence level of a one-sided Bayesian interval estimate of the parameter. This method results in direct determination of whether the proportion of defects P in the population is greater or less than a prespecified level d, rather than test two points as proxy for the decision. We present a numerical illustration of the rule and an example of determining rejection and acceptance numbers. Ue also compare the results with two conventional rules.

Keywords:

• acceptance sampling
• Bayesian
• one-sided confidence interval