X-Bar & R Charts are Control Charts designed for tracking the average of sub-grouped continuous data. They consist of two separate charts;  “X-Bar” stands for the “Average” Chart which tracks the mean of sub-groups of up to 6 data points and “R” stands for “Range” Chart which tracks the difference between the maximum and minimum values in the subgroup. These charts are not as sensitive to non-normal data as the I & MR Charts.

A classic example of an X-Bar & R Chart is to track the average cycle time to deliver packages by sampling 5 packages per day.

For a better understanding of the X-Bar & R Chart, check out our Black Belt Training & Certification Course!

Elisabeth Swan

Elisabeth is a Managing Partner & Executive Advisor at GoLeanSixSigma.com. For over 25 years, she's helped leading organizations like Amazon, Charles Schwab and Starwood Hotels & Resorts build problem-solving muscles with Lean Six Sigma to achieve their goals.

Tracy O'Rourke

Tracy is a Managing Partner & Executive Advisor at GoLeanSixSigma.com. For almost 20 years, she's helped leading organizations like Washington State, Cisco and GE build problem-solving muscles with Lean Six Sigma to achieve their goals.