Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt DMAIC: Improve and Control 1

Question 1

During the Improve phase, a team wants to test multiple input variables simultaneously to determine which combination produces the best output. Which statistical technique is best suited for this?

Accepted Answer

Design of Experiments (DOE)

Answer

Design of Experiments (DOE) allows teams to systematically test multiple input variables and their interactions simultaneously, making it the most efficient method for finding optimal process settings in the Improve phase.

Question 2

In the Control phase, a process owner notices the X-bar chart shows a single point beyond the upper control limit. According to standard control chart rules, this is an indication of:

Accepted Answer

A special cause variation requiring investigation

Answer

A single point beyond a control limit is one of the standard Western Electric rules for detecting special cause variation, which requires immediate investigation to identify and eliminate the assignable cause.

Question 3

A Lean Six Sigma team has completed the Improve phase and is transitioning to Control. Which document formally assigns ongoing monitoring responsibilities to specific process owners?

Accepted Answer

Control Plan

Answer

The control plan is the primary document in the Control phase that defines what to monitor, how to monitor it, measurement frequency, and who is responsible, ensuring the gains from the Improve phase are sustained.

Question 4

When using a Poka-Yoke (mistake-proofing) device as an improvement solution, the primary goal is to:

Accepted Answer

Make it impossible or immediately obvious when an error is about to happen

Answer

Poka-Yoke devices are designed to either prevent errors from occurring in the first place (prevention type) or detect them the moment they occur (detection type), eliminating reliance on human vigilance.

Question 5

After implementing process improvements, a team wants to confirm the new process mean is statistically different from the old baseline mean. Which statistical test should they use?

Accepted Answer

Two-Sample t-Test

Answer

A two-sample t-test compares the means of two independent groups (before and after improvement) to determine whether the difference is statistically significant, validating that the improvement had a real effect.

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt DMAIC: Improve and Control 1