Estimated incapability index: Reliability and decision making with sample information

Abstract

The process incapability index C-pp, which provides an uncontaminated separation between information concerning the process precision and process accuracy, has been proposed to measure process performance for industry applications. In this paper, we investigate the reliability of the natural estimator computationally, based on the alpha-level confidence relative error for various sample sizes. We also develop a decision-making procedure for judging if the process satisfies the preset quality requirement. The investigation is useful to the practitioners in determining the sample sizes required in their applications for the decisions reliable to the desired level. Copyright (C) 2002 John Wiley Sons, Ltd.