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210 A Graphical Approach to Obtaining Confidence Limits of C pk
and used the tolerance box to relate the confidence limits of C p , p, and k. We then
evaluated three approximate C pk confidence limits using simulation and proposed a
guide for practitioners to arrive at the ‘approximate method’ confidence limits. We
also demonstrated their usage via illustrative examples. These AM limits were shown
to have good coverage probabilities and short average confidence interval widths as
compared with three bootstrap confidence limits. Their performance is robust to the
sample size n and capability index C p .

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