I-MR chart

An I-MR chart is a combination of control charts used to monitor the process variability (as the moving range between successive observations) and average (as the mean) when measuring individuals at regular intervals from a process.

• I chart
  An I-chart is a type of control chart used to monitor the process mean when measuring individuals at regular intervals from a process.
• MR chart
  An MR-chart is a type of control chart used to process variability (as the moving range of successive observations) when measuring individuals at regular intervals from a process.