Lean Six Sigma Yellow Belt Certification Lean Six Sigma Yellow Belt The Control Phase 1

Question 1

In the Control phase, what is the primary purpose of a reaction plan?

Accepted Answer

To outline steps the team takes when a process metric goes out of control

Answer

A reaction plan specifies the predefined steps operators and supervisors must follow when a control chart signals an out-of-control condition, ensuring the process is corrected quickly and consistently without waiting for further analysis.

Question 2

Which of the following BEST describes mistake-proofing (Poka-Yoke) as a Control phase strategy?

Accepted Answer

Designing the process so errors are physically impossible or immediately detected

Answer

Poka-Yoke devices or design changes make it impossible or very difficult for a defect to occur or escape detection, which is a highly robust control method that does not rely on operator vigilance or periodic audits.

Question 3

A process capability index (Cpk) of 1.33 monitored during the Control phase generally indicates that the process is:

Accepted Answer

Capable and meeting specifications with a reasonable safety margin

Answer

A Cpk of 1.33 corresponds to roughly a 4-sigma process, meaning the process is producing output well within specification limits with an adequate buffer — it is considered capable but not yet at Six Sigma (Cpk ≈ 2.0) performance.

Question 4

What is the main purpose of conducting periodic process audits during the Control phase?

Accepted Answer

To verify that operators and the process continue to follow the improved standard work

Answer

Periodic audits confirm that the gains achieved during the Improve phase have been sustained — that operators are following updated procedures and the process has not reverted to old habits over time.

Question 5

Which control chart would be MOST appropriate for tracking the number of defects per unit when the subgroup size changes from sample to sample?

Accepted Answer

u-chart

Answer

The u-chart (defects per unit) is designed for situations where defect counts are tracked and the sample size varies between subgroups. The c-chart also tracks defect counts but assumes a constant sample size, making the u-chart the correct choice here.

Lean Six Sigma Yellow Belt Certification Practice Test

Lean Six Sigma Yellow Belt Certification Practice Test

Lean Six Sigma Yellow Belt Certification Lean Six Sigma Yellow Belt The Control Phase 1