Lean Six Sigma Green Belt Practice Exam Practice Test
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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.
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A multiple-choice exam. Practice by topic here, then take the full timed mock exam to gauge readiness.
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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 document the final control plan
- b.To perform hypothesis testing on the data
- c.To formally authorize the project and align the team on problem, scope, goal, and business case
- d.To calculate the process sigma level
Answer: c
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
The Champion of a Six Sigma project is typically:
- a.The frontline operator who collects the data
- b.A senior leader who removes barriers, secures resources, and aligns the project with strategy
- c.An outside auditor who independently certifies the final results and formally signs off on the reported savings
- d.The full-time technical expert who runs the statistics
Answer: b
Explanation: The Champion is a senior sponsor who provides resources, clears organizational roadblocks, and ties the project to business goals. Technical execution belongs to Belts, and data collection to team members.
- 3. Define
CTQs eventually connect to specification limits because:
- a.CTQs are always qualitative and unmeasurable
- b.Specification limits are chosen more or less randomly by the design team without reference to the customer
- c.Specification limits are set by the process, not the customer
- d.The customer's measurable requirement (CTQ) defines the acceptable range the process output must meet
Answer: d
Explanation: A CTQ translates a customer need into a measurable characteristic with target and tolerance; those tolerances become the specification limits (USL/LSL) the process is judged against. Specs derive from customer requirements, not process behavior.
- 4. Measure
A process makes 2,000 units, each with 10 opportunities, and produces 50 defects. What is the DPMO?
- a.500
- b.250
- c.1,000
- d.2,500
Answer: d
Explanation: DPMO = 50 / (2,000 x 10) x 1,000,000 = 50 / 20,000 x 1,000,000 = 2,500. Total opportunities are 20,000, and 50/20,000 = 0.0025, which is 2,500 per million.
- 5. Measure
The difference between Cp/Cpk and Pp/Ppk lies mainly in the standard deviation used: Cp/Cpk use within-subgroup (short-term) variation, while Pp/Ppk use:
- a.Overall (long-term) variation that includes shifts and drifts over time
- b.The number of opportunities
- c.Only the specification width
- d.The mode, meaning the single most frequently occurring value in the data set
Answer: a
Explanation: Cp/Cpk (potential capability) use short-term, within-subgroup sigma, whereas Pp/Ppk (process performance) use the overall long-term sigma, capturing between-subgroup drift. Performance indices are usually a bit lower than capability indices.
- 6. Analyze
In Lean, 'value-added' activity is best defined as work that:
- a.Inspects the finished product to detect and screen out defects
- b.Is any step at all that the operator happens to be paid to perform during the shift
- c.The customer will pay for, physically transforms the product, and is done right the first time
- d.Moves material or product between two adjacent workstations
Answer: c
Explanation: A value-added step meets three tests: the customer will pay for it, it changes the product toward what the customer wants, and it is done correctly the first time. Movement and inspection are classic non-value-added (though sometimes necessary) activities.
- 7. Analyze
A Green Belt should confirm the assumption of independence in a data sample because dependent (autocorrelated) data can:
- a.Only ever affect categorical chi-square tests and never any continuous-data tests
- b.Invalidate many standard hypothesis tests and understate the true variation
- c.Guarantee that the underlying process is fully capable
- d.Reliably improve the accuracy of every hypothesis test
Answer: b
Explanation: Many hypothesis tests assume independent observations; autocorrelation (for example, consecutive readings drifting together) violates that assumption and can produce misleading p-values and understated variance. Checking independence, often via a time-order run chart, protects the validity of the analysis.
- 8. Improve
When selecting among solutions, a 'must' criterion (a mandatory requirement such as regulatory compliance) should be treated as:
- a.Just one of many equally weighted 'want' criteria in the matrix
- b.An optional nice-to-have that can be traded away if needed
- c.A pass/fail filter that eliminates any solution failing it, regardless of other scores
- d.A factor entirely irrelevant to the final selection decision
Answer: c
Explanation: Mandatory 'must' criteria act as pass/fail gates: a solution that violates a legal or safety requirement is disqualified no matter how well it scores elsewhere. Only solutions clearing all musts are then ranked on the weighted 'want' criteria.
- 9. Control & Lean Fundamentals
A c chart monitors defects on assembled boards with c-bar = 9 defects per board. Using three-sigma limits, the UCL and LCL are:
- a.UCL = 12, LCL = 6
- b.UCL = 27, LCL = 0
- c.UCL = 18, LCL = 0
- d.UCL = 21, LCL = -3
Answer: c
Explanation: For a c chart, limits = c-bar plus/minus 3 x sqrt(c-bar) = 9 plus/minus 3 x sqrt(9) = 9 plus/minus 3 x 3 = 9 plus/minus 9. So UCL = 18 and the calculated LCL = 0. The Poisson square-root form drives the c chart limits.
- 10. Control & Lean Fundamentals
Adjusting a stable process in response to normal common-cause variation is called 'tampering.' Its effect is to:
- a.Reduce the process variation
- b.Have no effect at all
- c.Increase the overall variation and make the output worse
- d.Bring the process into specification automatically
Answer: c
Explanation: Tampering (over-adjusting a stable process, as in Deming's funnel experiment) adds adjustment-induced variation on top of the natural variation, worsening performance. Control charts prevent tampering by telling operators when NOT to react, that is, when variation is common-cause.