It's important to take the client seriously in every respect, especially about the little things.
- McCormack -
Average Run Length (ARL)
Assuming a process is in statistical control and the upper and lower control limits are known, the ARL is the expected number of subgroups inspected and measured before an operator detects whether a process has shifted to a new level of control with a new center line and control limits. There are statistical methods for calculating the ARL.
