A Note on the Factor Values of Three Common Shewhart Variables Control Charts
Henry H. Bi. 2015. A Note on the Factor Values of Three Common Shewhart Variables Control Charts. Communications in Statistics - Theory and Methods (0361-0926). 44(13): 2655-2673. DOI: 10.1080/03610926.2014.968732
Posted: 13 Nov 2014 Last revised: 26 Apr 2019
Date Written: 2015
It is a common practice that people directly use the published factor values in constructing Shewhart variables control charts. Currently, the values of most of the factors are published typically with up to 4 decimal places of precision and from sample size n = 2 through 25; a number of discrepancies in the published factor values from different sources also exist. In this paper, we compute and provide the factor values with more precision of 10 decimal places and consecutively through n = 100 for three commonly used variables control charts: xbar-R charts, xbar-s charts, and XmR charts.
Keywords: factor value; Shewhart variables control chart; xbar-R chart; xbar-s chart; XmR chart
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