Abstract:
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Although many studies have compared the ability of Shewhart, CUSUM, EWMA, etc. attribute control charts (p-chart, np-chart, c-chart, u-chart) in detecting a shift, few have analyzed the ability of these charts to detect trends, cycles, oscillations, and general instability. This is particularly true when the full set of evaluation rules are used with the Shewhart charts. This paper will report the Type II error and power of using the Shewhart chart in analyzing a variety of out-of-control processes. Each process will be analyzed using a variety of evaluation rules as well as a combination of the rules. These same processes will also be analyzed using a variety of non-Shewhart type control charts. A comparison of the different control charts and evaluation rules is provided. In order to measure the Type I error of each evaluation rule, as well as each non-Shewhart type control chart, a variety of in-control processes will be also analyzed.
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