Lean Six Sigma Green Belt Certification DMAIC: Analyze Phase Techniques 3

Question 1

A fishbone diagram is constructed and most causes cluster under the 'Methods' category. What should the team do next?

Accepted Answer

Conduct a 5 Why analysis on the 'Methods' causes to find root causes

Answer

After identifying the dominant category, 5 Why analysis drills deeper into that category to identify actual root causes.

Question 2

Which assumption must be verified before using a one-way ANOVA to compare means across three process lines?

Accepted Answer

Variances across groups must be approximately equal

Answer

One-way ANOVA assumes equal variances (homoscedasticity) across groups, which should be verified with Bartlett's or Levene's test.

Question 3

A process improvement team creates a scatter plot and finds points forming a curved (non-linear) pattern. What is the BEST next step?

Accepted Answer

Apply a data transformation or fit a non-linear regression model

Answer

When a scatter plot shows a non-linear pattern, a data transformation (e.g., log, square root) or non-linear regression model is appropriate.

Question 4

What is the primary purpose of a Failure Mode and Effects Analysis (FMEA) during the Analyze phase?

Accepted Answer

To prioritize potential failure modes by their Risk Priority Number (RPN)

Answer

FMEA identifies potential failure modes and scores them by RPN (Severity × Occurrence × Detection) to prioritize which risks to address.

Question 5

When conducting a 5 Why analysis, a team arrives at the same root cause from two different symptom branches. This most likely means:

Accepted Answer

A single systemic root cause drives multiple symptom paths

Answer

Converging paths in a 5 Why analysis often signal a single, systemic root cause that produces multiple downstream symptoms.

Lean Six Sigma Green Belt Certification Practice Test