Lean Six Sigma Green Belt Certification Improve Phase and Solutions 3 — Questions and Answers
Question 1: What is a 'fractional factorial' design used for in DOE?
- To increase the number of experimental runs for better accuracy
- To study a subset of all possible factor combinations and reduce runs (Correct answer)
- To eliminate all interaction effects from analysis
- To ensure full replication of every experimental condition
Correct answer: To study a subset of all possible factor combinations and reduce runs
Fractional factorial designs study a carefully chosen fraction of all factor combinations, reducing runs while still estimating main effects.
Question 2: A 5S implementation is underway. Which 'S' focuses on creating rules and schedules to maintain the improved workplace?
- Sort
- Set in Order
- Shine
- Standardize (Correct answer)
Correct answer: Standardize
Standardize (the 4th S) involves creating standards, procedures, and schedules that sustain the gains from the first three S activities.
Question 3: In a single-minute exchange of die (SMED) initiative, 'external setup' activities are those that:
- Can only be done while the machine is running (Correct answer)
- Must be done while the machine is stopped
- Require supervisor approval before starting
- Are documented in the standard work sheet
Correct answer: Can only be done while the machine is running
External setup activities can be performed while the machine is still running, unlike internal activities that require the machine to be stopped.
Question 4: Which statistical test is most appropriate to compare the means of three or more groups in an Improve phase validation?
- Paired t-test
- One-sample t-test
- One-way ANOVA (Correct answer)
- Chi-square test
Correct answer: One-way ANOVA
One-way ANOVA tests whether the means of three or more independent groups are statistically different.
Question 5: A kaizen event is best described as:
- A long-term strategic planning session
- A focused, short-duration team workshop to rapidly improve a specific process (Correct answer)
- A tool for monitoring process performance over time
- An annual performance review cycle
Correct answer: A focused, short-duration team workshop to rapidly improve a specific process
A kaizen event (or kaizen blitz) is an intensive, short-duration team effort—typically 3–5 days—to rapidly improve a targeted process area.
Question 6: Which of the following best describes 'pull' production in a lean system?
- Producing as much as possible to fill warehouse space
- Triggering production only when a downstream process signals demand (Correct answer)
- Scheduling production based on a fixed monthly forecast
- Assigning overtime when orders exceed capacity
Correct answer: Triggering production only when a downstream process signals demand
Pull production uses downstream demand signals (such as kanban cards) to trigger upstream production, preventing overproduction.
Question 7: During Improve phase solution selection, a solution scoring matrix (weighted criteria matrix) is used to:
- Identify root causes of the problem
- Objectively compare and rank potential solutions against weighted criteria (Correct answer)
- Monitor the implemented solution over time
- Document the project charter requirements
Correct answer: Objectively compare and rank potential solutions against weighted criteria
A weighted criteria (Pugh) matrix scores each solution alternative against important criteria weighted by importance to enable objective selection.
Lean Six Sigma Green Belt Certification Improve Phase and Solutions 3
What is a 'fractional factorial' design used for in DOE?