Quality control charts usually have a central line and upper and lower control limit lines. Which of the following is a reason that the process being monitored with the chart should be investigated?
A) A single point falls above or below the control limits.
B) Behavior is normal.
C) A large number of plots are on or near the central line.
D) There is no real trend in any direction.
E) There is a change in raw materials or operators.

Question

Quizplus · Accepted Answer

A single point falling above or below the control limits indicates an abnormality in the process and should be investigated. The other options do not necessarily require investigation.

Quality Control Charts Usually Have a Central Line and Upper