A sequential hypothesis testing procedure for the process capability index Cpk

In this study, we propose a sequential method for hypothesis testing on the Cpk process capability index. We compare the properties of the sequential test with the performances of nonsequential tests by performing an extensive simulation study. The results show that the proposed sequential test makes it possible to save a large amount of sample size as compared with the fixed sample size tests while maintaining the desired \u3b1\u2010level and power