Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt 1 — Questions and Answers
Question 1: What is the primary objective of the Analyze phase in DMAIC?
- Implement and pilot potential solutions
- Identify and verify the root causes of the problem (Correct answer)
- Establish baseline process performance metrics
- Define the project scope and customer requirements
Correct answer: Identify and verify the root causes of the problem
The Analyze phase focuses on using data and analytical tools (such as fishbone diagrams, regression, and hypothesis testing) to identify and statistically verify the true root causes of the problem before moving to solutions.
Question 2: Which process capability index accounts for BOTH process spread and process centering relative to specification limits?
- Cp
- Cpk (Correct answer)
- Pp
- Sigma level
Correct answer: Cpk
Cpk adjusts for how well the process mean is centered between the specification limits, making it a more complete measure than Cp, which only considers spread. A process can have a high Cp but a low Cpk if it is off-center.
Question 3: In Lean methodology, which of the following best describes the waste of 'Overproduction'?
- Producing items that do not meet customer quality standards
- Producing more output than the customer currently needs (Correct answer)
- Moving materials unnecessarily between workstations
- Waiting for upstream processes to deliver work
Correct answer: Producing more output than the customer currently needs
Overproduction—making more than is needed, sooner than needed—is considered the worst of the eight Lean wastes because it generates or hides most of the other wastes such as inventory, transportation, and defects.
Question 4: A Fishbone (Ishikawa) diagram is primarily used to:
- Plot defect frequency in descending order to identify the vital few
- Organize and display potential root causes grouped by category (Correct answer)
- Track process output over time to detect special-cause variation
- Map the sequence of steps in a process from input to output
Correct answer: Organize and display potential root causes grouped by category
The Fishbone diagram structures brainstormed potential causes into categories (e.g., Man, Machine, Method, Material, Measurement, Environment), helping teams systematically explore why a problem exists without jumping to solutions.
Question 5: In hypothesis testing, if the p-value is 0.03 and the significance level (α) is 0.05, the correct conclusion is:
- Fail to reject the null hypothesis; the difference is not significant
- Reject the null hypothesis; the result is statistically significant (Correct answer)
- Accept the alternative hypothesis with 97% certainty
- Increase the sample size before drawing any conclusion
Correct answer: Reject the null hypothesis; the result is statistically significant
When the p-value (0.03) is less than α (0.05), there is sufficient statistical evidence to reject the null hypothesis. This means the observed effect is unlikely due to random chance at the chosen confidence level.
Question 6: What does the Risk Priority Number (RPN) in a Failure Mode and Effects Analysis (FMEA) represent?
- The percentage of defects caused by a specific failure mode
- The product of Severity, Occurrence, and Detection ratings (Correct answer)
- The number of defects per million opportunities for a process step
- The difference between the Upper and Lower Control Limits
Correct answer: The product of Severity, Occurrence, and Detection ratings
RPN = Severity × Occurrence × Detection. This composite score helps teams prioritize which failure modes need immediate corrective action, with higher RPNs indicating greater risk requiring attention first.
Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt 1
What is the primary objective of the Analyze phase in DMAIC?