XBar-R chart calculations

XBar-R chart control limits are calculated as follows:

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 (when subgroup size is from 2 - 25).

Data Plot Items

• Subgroup Mean (upper chart)

• Subgroup Range (lower chart)

• 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)

See Also

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