Certified Six Sigma Black Belt Exam FREE Certified Six Sigma Black Belt Statistical Process Control (SPC) Questions and Answers 2

Question 1

A process has a Cp of 1.33 and a Cpk of 0.89. What does this indicate?

Accepted Answer

The process is capable but not centered within the specification limits

Answer

When Cp exceeds Cpk, it indicates the process has adequate spread relative to specifications but the mean has shifted away from the center of the tolerance band.

Question 2

Which control chart is most appropriate for monitoring the number of paint defects found on each automobile body panel when the inspection area varies by panel size?

Accepted Answer

u-chart

Answer

The u-chart tracks defects per unit of measure, making it appropriate when the sample size or area of opportunity varies between subgroups.

Question 3

On an X-bar and R chart, what is the primary purpose of rational subgrouping?

Accepted Answer

To group data so that special cause variation appears between subgroups rather than within them

Answer

Rational subgrouping arranges data so that common cause variation is captured within subgroups, causing any special cause variation to show up as differences between subgroup averages.

Question 4

A process is in statistical control but producing 4% nonconforming output. What is the correct course of action?

Accepted Answer

Implement fundamental process changes to reduce common cause variation

Answer

A stable process producing unacceptable defect levels requires management action to change the system and reduce common cause variation, not tampering or tighter chart limits.

Question 5

What does the Western Electric Rule for 2 out of 3 consecutive points beyond 2 sigma indicate on a control chart?

Accepted Answer

A potential small shift in the process mean

Answer

The 2-of-3 beyond 2-sigma rule is a sensitizing rule designed to detect small sustained shifts in the process mean that a single point beyond 3-sigma might miss.

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam FREE Certified Six Sigma Black Belt Statistical Process Control (SPC) Questions and Answers 2