Lean Six Sigma Green Belt Practice Exam Practice Test
Frequently asked questions
How many Lean Six Sigma Green Belt Practice Exam practice questions are here?+
A full bank of original Lean Six Sigma Green Belt Practice Exam practice questions across the official content areas, weighted like the real exam, with explanations. Free, no signup.
What is the Lean Six Sigma Green Belt Practice Exam exam like?+
A multiple-choice exam. Practice by topic here, then take the full timed mock exam to gauge readiness.
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No. Every question is 100% original, written from public primary sources with explanations. We never copy real exam questions or paid prep material.
Can I study in Chinese or Spanish?+
PrepPass practice is in English, 中文 and Español. The official exam is in English — switch the question language to English any time to rehearse the exact terminology you'll see on test day.
Sample practice questions
A few real questions from this free bank, with full explanations. Use the practice tool above for the whole set.
- 1. Define
In the Define phase, what is the primary purpose of a project charter?
- a.To calculate the process sigma level
- b.To formally authorize the project and align the team on problem, scope, goal, and business case
- c.To document the final control plan
- d.To perform hypothesis testing on the data
Answer: b
Explanation: The charter is the foundational Define deliverable: it states the problem, scope, goal, business case, team, and timeline so the project is authorized and everyone shares the same objective. Sigma calculations, control plans, and hypothesis tests come in later DMAIC phases.
- 2. Define
"Critical to Quality" (CTQ) characteristics are best described as:
- a.Measurable product or process features that translate the customer's needs into requirements
- b.The team members assigned to the project
- c.The control limits on a process behavior chart
- d.Non-value-added steps in the value stream
Answer: a
Explanation: CTQs convert the Voice of the Customer into specific, measurable requirements the process must meet. They are derived from customer needs, not from team rosters, control charts, or waste categories.
- 3. Measure
A process inspects 500 units, each having 8 opportunities for a defect, and finds 20 defects. What is the DPMO?
- a.2,500
- b.5,000
- c.40,000
- d.250
Answer: b
Explanation: DPMO = defects / (units x opportunities) x 1,000,000 = 20 / (500 x 8) x 1,000,000 = 20 / 4,000 x 1,000,000 = 5,000. Each answer that ignores the opportunity count or the scaling factor is incorrect.
- 4. Measure
Using the common long-term sigma table (with the 1.5-sigma shift), a process operating at approximately 66,807 DPMO corresponds to what sigma level?
- a.6 sigma
- b.4 sigma
- c.3 sigma
- d.2 sigma
Answer: c
Explanation: On the standard shifted sigma table, roughly 66,807 DPMO equals about a 3-sigma process (about 93.3% yield). Six sigma is about 3.4 DPMO and four sigma is about 6,210 DPMO.
- 5. Measure
In a Measurement System Analysis (Gage R&R), 'reproducibility' refers to the variation caused by:
- a.The same appraiser measuring the same part repeatedly
- b.Different appraisers measuring the same part with the same gage
- c.The natural variation of the manufacturing process
- d.The width of the specification tolerance
Answer: b
Explanation: Reproducibility is the appraiser-to-appraiser (between-operator) variation. The same appraiser repeating a measurement is repeatability, and neither describes process variation or the tolerance itself.
- 6. Analyze
A correlation coefficient (r) of 0.85 between two variables indicates:
- a.That one variable definitely causes the other
- b.A strong positive linear relationship between the variables
- c.No relationship between the variables
- d.A strong negative linear relationship
Answer: b
Explanation: An r near +0.85 signals a strong positive linear association, meaning the variables tend to rise together. Correlation alone never proves causation, and a negative relationship would show a negative r.
- 7. Analyze
In hypothesis testing, a Type I error (alpha) occurs when you:
- a.Reject a null hypothesis that is actually true (a false positive)
- b.Fail to reject a null hypothesis that is actually false
- c.Choose too large a sample size
- d.Measure a part with the wrong gage
Answer: a
Explanation: A Type I error is a false positive: concluding an effect exists when it does not, which happens with probability alpha. Failing to detect a real effect is a Type II (beta) error.
- 8. Improve
Poka-yoke, applied in the Improve phase, refers to:
- a.A statistical sampling plan
- b.A capacity-planning calculation
- c.Mistake-proofing that prevents or immediately detects errors
- d.A supplier scorecard
Answer: c
Explanation: Poka-yoke is error- or mistake-proofing that makes a defect impossible or obvious, such as a connector that only fits one way. It is a prevention technique, not a sampling, capacity, or supplier-rating method.
- 9. Control & Lean Fundamentals
The main purpose of a control chart in the Control phase is to:
- a.Distinguish common-cause variation from special-cause variation over time
- b.Rank problems from most to least frequent
- c.Map the suppliers and customers of a process
- d.Prove a factor is statistically significant
Answer: a
Explanation: Control charts plot data over time with control limits so teams can tell routine common-cause variation from special-cause signals that need action. Ranking, mapping, and significance testing are done with other tools.
- 10. Control & Lean Fundamentals
In Lean, which of the following is one of the classic categories of waste (muda)?
- a.Standardized work
- b.Value-added processing
- c.Overproduction
- d.Continuous flow
Answer: c
Explanation: Overproduction, making more or sooner than needed, is one of the classic wastes and is often called the worst because it hides others. Standardized work, value-added processing, and continuous flow are goals, not wastes.