Univariate and Multivariate Process Capability Analysis for Different Types of Specification Limits

Abstract

In the context of statistical quality control, process capability index (PCI) is one of the widely accepted approaches for assessing the performance of a process with respect to the pre-assigned specification limits. The quality characteristic under consideration can have differnt types of specification limits like bilateral, unilateral, circular and so on. Use of single PCI for all the situations could be misleading. Hence appropriate PCIs need to be chosen based on the characteristics of the specification limits. Similar situations may arise for multivariate characteristics as well. In the present chapter, we have discussed about some of the PCIs for different specification limits including some PCIs for multivariate characteristics. A few numerical examples are given to suppliment our theoretical discussion.