Lean Six Sigma Green Belt Certification Assessment 5

Question 1

A Green Belt is assessing whether a process change has had a statistically significant impact on defect rates. Before the change: 45 defects in 500 units. After: 20 defects in 500 units. Which test is most appropriate?

Accepted Answer

Two-proportion z-test

Answer

Comparing two proportions (defect rates) from two independent samples before and after a change requires a two-proportion z-test.

Question 2

During a Lean assessment, a team identifies buffer inventory between process steps. This inventory is classified as which type of waste?

Accepted Answer

Inventory

Answer

Excess buffer or work-in-process inventory between steps is classified as inventory waste, one of the original seven wastes (muda) in Lean thinking.

Question 3

A Green Belt assesses whether cycle time data follows a normal distribution before performing capability analysis. Which tool is most appropriate for this assessment?

Accepted Answer

Probability plot (normal probability plot)

Answer

A normal probability plot (also called a normal plot or Q-Q plot) graphically assesses whether data follows a normal distribution by checking how closely points follow a straight line.

Question 4

In a Lean Six Sigma project assessment, the team is reviewing the Analyze phase outputs. Which deliverable confirms the project has correctly identified root causes before moving to Improve?

Accepted Answer

A validated fishbone with statistical evidence linking Xs to Ys

Answer

Moving from Analyze to Improve requires validated root causes where statistical analysis has confirmed the relationship between input variables (Xs) and output measures (Ys).

Question 5

A Green Belt assesses the results of a designed experiment (DOE). A main effects plot shows a steep slope for Factor A and a nearly flat line for Factor B. This indicates:

Accepted Answer

Factor A has a larger effect on the response than Factor B

Answer

In a main effects plot, steeper slopes indicate greater impact on the response variable; Factor A's steep slope shows it has a much larger effect than Factor B.

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Assessment 5