SPC Control Charts & Analysis

Question 1

What is the purpose of the center line on a control chart?

Accepted Answer

Process mean

Answer

The center line represents the average or mean of the process and serves as a reference for detecting variation.

Question 2

What does it indicate when points trend steadily upward on a control chart?

Accepted Answer

Possible process shift

Answer

A continuous upward trend may signal a shift in the process mean, requiring investigation.

Question 3

Which type of control chart is best for monitoring process variability?

Accepted Answer

R-chart

Answer

R-charts monitor the range of variation within subgroups, making them useful for detecting shifts in variability.

Question 4

How many standard deviations from the mean are typical control limits set at?

Accepted Answer

3

Answer

Control limits are generally placed at ±3 standard deviations to detect statistically significant variation.

Question 5

Which of the following may indicate a process is out of control?

Accepted Answer

One point outside control limits

Answer

A single point outside the control limits is a common signal that the process may be out of control.

(SPC) Statistical Process Control Certification Practice Test