Lean Six Sigma Green Belt Certification DMAIC: Improve and Control 4

Question 1

Which metric best quantifies the long-term process capability when the process mean is not centered between specification limits?

Accepted Answer

Ppk

Answer

Ppk measures long-term process performance accounting for both the actual process spread and how far the mean is from the nearest specification limit.

Question 2

A team wants to reduce setup time on a manufacturing line. Which Lean technique specifically targets the reduction of changeover time?

Accepted Answer

SMED (Single-Minute Exchange of Die)

Answer

SMED is a systematic approach to reduce changeover time by converting internal setup steps (done while the machine is stopped) to external steps (done while it runs).

Question 3

What is the key difference between corrective action and preventive action in a control plan?

Accepted Answer

Corrective action responds to an out-of-control event; preventive action eliminates potential causes before they occur

Answer

Corrective action is reactive, taken after a defect or special cause is detected, while preventive action is proactive, removing the root cause of a potential failure before it materializes.

Question 4

A process has a Cpk of 0.85. What does this indicate?

Accepted Answer

The process is producing defects and is not fully capable

Answer

A Cpk below 1.0 indicates the process is producing output outside the specification limits and is not yet capable of meeting customer requirements.

Question 5

During an experiment, a team notices that temperature and pressure consistently change together across runs. This is an example of which experimental design problem?

Accepted Answer

Confounding due to lurking variable

Answer

When two variables move together unintentionally across experimental runs, their effects become entangled, making it impossible to attribute results to either factor independently.

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification DMAIC: Improve and Control 4