Lean Six Sigma Green Belt Certification Knowledge 2 — Questions and Answers
Question 1: In the DMAIC methodology, which phase focuses on identifying and validating the root causes of defects?
- Define
- Measure
- Analyze (Correct answer)
- Control
Correct answer: Analyze
The Analyze phase uses tools like fishbone diagrams and hypothesis testing to identify and confirm root causes.
Question 2: What does a Cp value of 1.33 indicate about a process?
- The process is barely capable
- The process is not capable
- The process is capable with some margin (Correct answer)
- The process is highly capable
Correct answer: The process is capable with some margin
A Cp of 1.33 means the process spread fits within specification limits with adequate margin, meeting the minimum industry standard for capable processes.
Question 3: Which type of data is best represented by a p-chart in statistical process control?
- Continuous measurement data
- Proportion of defective units (Correct answer)
- Number of defects per unit
- Time between failures
Correct answer: Proportion of defective units
A p-chart tracks the proportion (fraction) of defective items in subgroups of varying or constant size.
Question 4: A Lean Six Sigma team discovers a process step that adds cost but no customer value. This step is classified as:
- Value-added
- Business value-added
- Non-value-added (Correct answer)
- Required waste
Correct answer: Non-value-added
Any step that adds cost without transforming the product in a way the customer values is non-value-added waste and should be eliminated.
Question 5: What is the primary purpose of a SIPOC diagram?
- To map detailed process steps with cycle times
- To provide a high-level view of the process scope and key elements (Correct answer)
- To identify the root cause of variation
- To track defects over time
Correct answer: To provide a high-level view of the process scope and key elements
A SIPOC (Suppliers, Inputs, Process, Outputs, Customers) diagram gives a concise high-level overview used early in the Define phase to scope the project.
Question 6: In hypothesis testing, a Type II error occurs when:
- A true null hypothesis is rejected
- A false null hypothesis is not rejected (Correct answer)
- The significance level is set too low
- The sample size is too large
Correct answer: A false null hypothesis is not rejected
A Type II error (beta error) is failing to reject a null hypothesis that is actually false — missing a real effect.
Question 7: Which Lean concept describes producing only what is needed, when it is needed, and in the amount needed?
- Kaizen
- Just-In-Time (JIT) (Correct answer)
- Jidoka
- Heijunka
Correct answer: Just-In-Time (JIT)
Just-In-Time is a Lean pillar that eliminates overproduction by synchronizing production flow with actual demand.
Lean Six Sigma Green Belt Certification Knowledge 2
In the DMAIC methodology, which phase focuses on identifying and validating the root causes of defects?