Sigma chart calculations

Sigma chart control limits are calculated as follows:

Sigma chart calculations
Control Limits calculated from data	Control Limits calculated from standard deviation (s ) are given)
is calculated using subgroup standard deviations instead of subgroup ranges. For more information, see Estimated Sigma.

NOTE: If subgroup size is variable, m is replaced with m_i for i^th subgroup limits. When subgroup size is variable, the control limit values will not be the same; therefore, the chart may display `city skyline' type control lines.

Data Plot Items

Subgroup Sigma
Lower Control Limit (LCL) (optional)
Upper Control Limit (UCL) (optional)
Warning lines (optional)

Descriptive Statistics

Lower Control Limit (LCL)
Upper Control Limit (UCL)
Center Line (CL)

Sigma chart calculations

Data Plot Items

Descriptive Statistics

See Also