Lean Six Sigma Black Belt Practice Exam Questions And
Correct Answers (Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of the Define phase in DMAIC?
A) Identify process defects
B) Implement process improvements
C) Define project goals and scope
D) Control future process performance
Rationale: The Define phase establishes the project charter, scope,
objectives, and customer requirements.
2. Which tool is commonly used to identify the voice of the
customer (VOC)?
A) Control chart
B) Pareto chart
C) SIPOC diagram
D) Histogram
Rationale: SIPOC (Suppliers, Inputs, Process, Outputs, Customers)
helps capture VOC and high-level process understanding.
3. In Six Sigma, a defect is defined as:
A) Any variation in a process
B) A customer complaint
C) Failure to meet customer specifications
D) A process improvement opportunity
Rationale: A defect occurs when a process output does not meet the
defined customer requirements.
4. What does DPMO stand for?
A) Defects per million outputs
B) Defects per million opportunities
C) Defects per measurement observation
,D) Defective parts measured objectively
Rationale: DPMO measures process performance relative to the
number of opportunities for defects.
5. Which metric is used to measure process capability?
A) Standard deviation
B) Mean
C) Cp and Cpk
D) Range
Rationale: Cp and Cpk indicate how well a process can meet
specifications.
6. What is the primary purpose of a SIPOC diagram?
A) Identify root causes
B) Analyze process variation
C) Provide a high-level process overview
D) Measure defects
Rationale: SIPOC summarizes the process from suppliers to customers
at a high level.
7. Which of the following is a Lean principle?
A) Increase inventory
B) Increase process complexity
C) Eliminate waste
D) Reduce customer interaction
Rationale: Lean focuses on reducing waste to improve efficiency and
value to the customer.
8. In DMAIC, which phase focuses on identifying root causes of
defects?
A) Define
B) Measure
C) Analyze
D) Improve
, Rationale: The Analyze phase uses data and statistical tools to
identify root causes.
9. Which tool is best for visually identifying the frequency of
problems?
A) Scatter plot
B) Control chart
C) Pareto chart
D) Cause-and-effect diagram
Rationale: Pareto charts show the most frequent issues, based on the
80/20 principle.
10. What is the purpose of a control chart?
A) Track project costs
B) Monitor process stability over time
C) Identify root causes
D) Define customer requirements
Rationale: Control charts display process performance and detect
variation over time.
11. Which type of variation is due to common causes?
A) Special cause variation
B) Natural variation inherent to the process
C) Defective variation
D) Process error variation
Rationale: Common cause variation is inherent and predictable;
special cause variation is assignable.
12. Which tool helps identify potential causes for a problem in a
structured way?
A) Histogram
B) Fishbone (Ishikawa) diagram
C) Control chart
D) Scatter plot
Correct Answers (Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of the Define phase in DMAIC?
A) Identify process defects
B) Implement process improvements
C) Define project goals and scope
D) Control future process performance
Rationale: The Define phase establishes the project charter, scope,
objectives, and customer requirements.
2. Which tool is commonly used to identify the voice of the
customer (VOC)?
A) Control chart
B) Pareto chart
C) SIPOC diagram
D) Histogram
Rationale: SIPOC (Suppliers, Inputs, Process, Outputs, Customers)
helps capture VOC and high-level process understanding.
3. In Six Sigma, a defect is defined as:
A) Any variation in a process
B) A customer complaint
C) Failure to meet customer specifications
D) A process improvement opportunity
Rationale: A defect occurs when a process output does not meet the
defined customer requirements.
4. What does DPMO stand for?
A) Defects per million outputs
B) Defects per million opportunities
C) Defects per measurement observation
,D) Defective parts measured objectively
Rationale: DPMO measures process performance relative to the
number of opportunities for defects.
5. Which metric is used to measure process capability?
A) Standard deviation
B) Mean
C) Cp and Cpk
D) Range
Rationale: Cp and Cpk indicate how well a process can meet
specifications.
6. What is the primary purpose of a SIPOC diagram?
A) Identify root causes
B) Analyze process variation
C) Provide a high-level process overview
D) Measure defects
Rationale: SIPOC summarizes the process from suppliers to customers
at a high level.
7. Which of the following is a Lean principle?
A) Increase inventory
B) Increase process complexity
C) Eliminate waste
D) Reduce customer interaction
Rationale: Lean focuses on reducing waste to improve efficiency and
value to the customer.
8. In DMAIC, which phase focuses on identifying root causes of
defects?
A) Define
B) Measure
C) Analyze
D) Improve
, Rationale: The Analyze phase uses data and statistical tools to
identify root causes.
9. Which tool is best for visually identifying the frequency of
problems?
A) Scatter plot
B) Control chart
C) Pareto chart
D) Cause-and-effect diagram
Rationale: Pareto charts show the most frequent issues, based on the
80/20 principle.
10. What is the purpose of a control chart?
A) Track project costs
B) Monitor process stability over time
C) Identify root causes
D) Define customer requirements
Rationale: Control charts display process performance and detect
variation over time.
11. Which type of variation is due to common causes?
A) Special cause variation
B) Natural variation inherent to the process
C) Defective variation
D) Process error variation
Rationale: Common cause variation is inherent and predictable;
special cause variation is assignable.
12. Which tool helps identify potential causes for a problem in a
structured way?
A) Histogram
B) Fishbone (Ishikawa) diagram
C) Control chart
D) Scatter plot
