Process Capability Indices are used in the industry as decision making tools. The values of the indices are estimated from a sample and should be qualified. Qualification of an estimate is provided in the form of a confidence interval for the estimate or from a hypothesis test. Cp and Cpk are two of the most widely used process capability indices in industry.
A hypothesis test for Cp has been developed by Kane (1986). The aim of this thesis is to develop a hypothesis test for Cpk. The hypothesis test for Cpk is developed from the approximate two sided confidence interval by Nagata and Nagahata (1992 & 1994). An Excel application has been developed which allows the user to compute cut-off and sample sizes for user-defined sampling plans. The application also computes Cp and Cpk and their confidence intervals from process data.