CQE Statistical Process Control

Question 1

What does a control chart's Upper Control Limit (UCL) represent in Statistical Process Control?

Accepted Answer

Three standard deviations above the process mean

Answer

The specification limit set by the customer

Answer

The maximum allowable defect rate

Answer

The target value for the process

Question 2

Which control chart is most appropriate for monitoring the number of defects per unit when the sample size varies?

Accepted Answer

u-chart

Answer

p-chart

Answer

c-chart

Answer

np-chart

Question 3

A process capability index (Cpk) of 1.33 indicates the process is:

Accepted Answer

Capable with a safety margin

Answer

Barely capable of meeting specifications

Answer

Out of control

Answer

Centered exactly on the target

Question 4

What is the primary purpose of a Western Electric (WECO) rule in SPC?

Accepted Answer

To detect non-random patterns indicating a special cause

Answer

To set specification limits

Answer

To calculate the process sigma level

Answer

To determine sample size

Question 5

In an X-bar and R chart, which component measures within-subgroup variation?

Accepted Answer

R chart

Answer

X-bar chart

Answer

Both charts equally

Answer

Neither chart directly

Question 6

A process with Cp = 1.5 but Cpk = 0.8 tells you that the process is:

Accepted Answer

Highly capable but significantly off-center

Answer

Capable and well-centered

Answer

Incapable regardless of centering

Answer

Correctly centered but has high variation