If a process control chart has only one point outside the upper or lower control limits, there is insufficient evidence to conclude that the process was out of control at the time that the measurement was taken.

Question

Quizplus · Accepted Answer

A single point outside the control limits on a process control chart is considered evidence that the process may have been out of control at the time the measurement was taken, as it indicates a variation beyond what is expected from common cause variation.

If a Process Control Chart Has Only One Point Outside