A quality engineer monitors the manufacture of liquid detergent and wants to assess whether the process is in control. The engineer measures the pH of 25 consecutive batches of detergent.
The engineer creates a Moving Range chart to monitor the detergent process.
None of the points are outside the control limits, and the points display a random pattern on the moving range chart. Thus, the process variation is in control, and the engineer can use the Individuals chart to examine the process center.