Which of the following would be considered to be a nonrandom pattern on a control chart?
A) 2 out of 3 data points above the grand mean.
B) 5 successive points between -1 and +1 sigma
C) 1 data point above -1 sigma or below +1 sigma
D) 14 points in a row, alternating up and down

Question

Quizplus · Accepted Answer

D) 14 points in a row, alternating up and down is considered a nonrandom pattern because it suggests a systematic variation in the process, which is not expected in a process that is in control and exhibiting random variation.

Which of the Following Would Be Considered to Be a Nonrandom