XBar-S chart calculations

XBar-S chart control limits are calculated as follows:

XBar-S chart calculations
	Control Limits calculated from data	Control Limits calculated from standard (mean ( µ ) and/or standard deviation (s ) are given)
XBar chart control limits
Sigma chart control limits	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 Mean (upper chart)
Subgroup Sigma (lower chart)
Lower Control Limit (LCL) (optional)
Upper Control Limit (UCL) (optional)
Warning lines (optional)

Descriptive Statistics Displayed

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

XBar-S chart calculations

Data Plot Items

Descriptive Statistics Displayed

See Also