Methods for Estimating the Standard Deviation
When control limits are determined from the input data, three
methods (referred to as default, MVLUE, and RMSDF) are available with
the MCHART statement for
estimating the process standard deviation .The method used to calculate depends on whether
you specify the STDDEVIATIONS option in the MCHART statement. If
this option is specified, is estimated using subgroup
standard deviations; otherwise, is estimated using
For further details and formulas, see "Methods for Estimating the Standard Deviation"
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