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