Process Sigma based on Sigma Chart

The process sigma of the subgroups.

Note: This is the standard deviation of the observations, NOT the standard deviation of the subgroup averages, which is calculated by dividing the standard deviation of the observations by the square root of n (the subgroup size).

  (n = constant) , OR

 (n ≠ constant)

where:

Sj is the Subgroup Sigma of subgroup j

S-bar is the Average Sigma

m is the total number of subgroups included in the analysis

c4 is a function of n

gj and hj are Burr constants

See also:

Process Sigma based on Range Chart

Process Sigma based on Moving Range Chart

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