X bar R Chart Formulas

The X bar R chart can help you evaluate the stability of processes using variable data--time, cost, length, weight when you have 2 to 10 samples per period.

Here are the X bar R chart formulas used in the QI Macros for both the Range and Average (Xbar) charts.

XbarR chart formulas

Conforms with ANSI/ASQC B1, B2, B3 1996

Process: Calculate, plot, and evaluate the range chart first. If it is "out of control," so is the process. If the range chart looks okay, then calculate, plot, and evaluate the X chart.

Other Resources

The X bar R chart is just one of the tools included in the QI Macros for Excel SPC Software for Excel.

To create a X Bar R Chart using QI Macros...
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