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Lean Six Sigma Practice Test

60 practice questions across 6 topics, each with a written explanation of why the correct answer is correct. Start below — the first questions are free and no account is required.

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Topics on the Lean Six Sigma exam

Sample Lean Six Sigma questions

DMAIC Framework

Which phase of DMAIC focuses on identifying and verifying root causes of a defect?

  1. A. Improve
  2. B. Define
  3. C. Measure
  4. D. Analyse

Answer: D. The Analyse phase uses statistical and qualitative tools (fishbone diagrams, 5 Whys, hypothesis testing, regression) to identify and verify root causes. You don't move to Improve until root causes are confirmed with data.

Process Capability (Cp, Cpk, Sigma Level)

What is the difference between Cp and Cpk?

  1. A. Cp is for two-sided specs; Cpk is for one-sided specs
  2. B. Cp uses the mean; Cpk uses the median
  3. C. Cp measures long-term capability; Cpk measures short-term capability
  4. D. Cp measures potential capability (centered); Cpk accounts for process centering

Answer: D. Cp (process capability ratio) measures potential capability assuming the process is perfectly centered between the specification limits. Cpk is the actual capability index — it accounts for where the process mean sits relative to both limits. A process can have high Cp (wide spec relative to variation) but low Cpk if the mean is off-center.

Control Charts (X-bar, R, P, C, U charts)

Which control chart is used to monitor the proportion of defective items in a sample of variable size?

  1. A. u chart
  2. B. c chart
  3. C. np chart
  4. D. p chart

Answer: D. The p chart monitors the proportion (fraction) of defective units. It is used when sample sizes vary. The np chart monitors the number of defective units but requires constant sample size. The c chart monitors defects per unit with constant sample size, and the u chart monitors defects per unit with variable sample size.

Work through every topic on the Lean Six Sigma question directory, or start the timed practice test above.

Lean Six Sigma exam — frequently asked questions

How many questions are on the Lean Six Sigma exam?

The Lean Six Sigma exam typically has 150 (CSSBB) / 110 (CSSGB). The exact count varies by state and exam version. VoltExam gives you 60 practice questions covering every topic tested.

What score do you need to pass the Lean Six Sigma exam?

The passing score for the Lean Six Sigma exam is typically 550/750 scaled (ASQ). Scoring significantly above the minimum on practice tests before exam day is strongly recommended to account for real-exam pressure.

What is the pass rate for the Lean Six Sigma exam?

The estimated first-attempt pass rate for the Lean Six Sigma exam is ~55%. Candidates who complete structured practice sessions with full answer explanations pass at significantly higher rates.

How long should I study for the Lean Six Sigma exam?

Most candidates study 2–4 months for the Lean Six Sigma exam. Study time varies based on prior experience. Focusing on practice questions with explanations is the most time-efficient preparation method.

What topics are on the Lean Six Sigma exam?

The Lean Six Sigma exam covers topics including: DMAIC Framework, Process Capability (Cp, Cpk, Sigma Level), Control Charts (X-bar, R, P, C, U charts), Hypothesis Testing & Statistics, Lean Tools & Waste Reduction, and 1 more topic areas. VoltExam's free study mode organizes 60 quick-study questions by concept so you can target weak areas efficiently.