Lean Six Sigma Practice Test

80 questions of our own on what every belt shares: lean, then Define, Measure, Analyze, Improve and Control.

An assembler walks across the shop to fetch a tool for every unit. Which waste is this?

Pick an answer, then press Check answer. Then you see Correct or Not quite, with the reason. Keys: A to D pick, Enter checks.

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Unofficial practice questions, not affiliated with ASQ (the American Society for Quality) or any other certifying body. Bank checked October 7, 2026.

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All 80 questions

Lean and Six Sigma basics 15

  • A machine inspects each item it makes, and stops and calls for help when it finds a defect. What is this form of automation called? ASQ Quality Glossary, entry "Autonomation"
  • A storeroom holds three months of a part the line uses every day. Which waste is this? ASQ Quality Glossary, entry "Eight wastes"
  • An assembler walks across the shop to fetch a tool for every unit. Which waste is this? ASQ Quality Glossary, entry "Eight wastes"
  • From a lean point of view, when does an activity count as value-added? ASQ Quality Resources, "Value Stream Mapping"
  • In 5S, what is done in set in order (seiton)? ASQ Quality Resources, "What are the Five S's (5S) of Lean?"
  • Lean reaches its goals with less-technical tools. Which set is given as typical of lean? ASQ Quality Resources, "What is Six Sigma?"
  • On which two pillars is the Toyota production system based? ASQ Quality Glossary, entry "Toyota production system (TPS)"
  • People, machines and materials are arranged so that the processing steps sit next to each other in sequence. What is the most common layout for such a cell? ASQ Quality Glossary, entry "Cell"
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Lean and Six Sigma basics, continued

  • Products go through each step one at a time, without waiting in lots between steps. What is this the opposite of? ASQ Quality Glossary, entry "One-piece flow"
  • Seven wastes were listed first. Which was added later as the eighth? ASQ Quality Glossary, entry "Eight wastes"
  • Six Sigma aims to cut process variation. What does lean drive out? ASQ Quality Resources, "What is Six Sigma?"
  • To draw a current state map, a team is told to go to the gemba. What is the gemba? ASQ Quality Resources, "Value Stream Mapping"
  • Where does a successful lean Six Sigma implementation often begin? ASQ Quality Resources, "What is Six Sigma?"
  • Which acronym is used to remember the eight wastes of lean? ASQ Quality Resources, "What is Lean?"
  • Why is the combined term "lean Six Sigma" used more and more often? ASQ Quality Resources, "What is Six Sigma?"

Define 13

  • A project aims to cut cycle time, and the team also tracks the error rate in case speed makes it worse. What is the error rate here? ASQ, Certified Six Sigma Green Belt Body of Knowledge (2022), section II.C.4
  • A SIPOC diagram can be extended to SIPOC+CM. What do the C and the M add? ASQ Quality Resources, "SIPOC+CM Diagram"
  • DMAIC suits most projects. For which kind of problem is it recommended in particular? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • During a brainstorming session, when are the ideas discussed or reviewed? ASQ Quality Glossary, entry "Brainstorming"
  • In a SIPOC diagram, what goes in the suppliers block? ASQ Quality Resources, "SIPOC+CM Diagram"
  • In the teamwork approach to DMAIC, how do members fit the project into their jobs? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • In which DMAIC phase is the project charter created? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • What does a project sponsor do? ASQ Quality Glossary, entry "Sponsor"
  • What does quality function deployment translate customer needs into? ASQ Quality Glossary, entry "Quality function deployment (QFD)"
  • What does the Pareto principle, the "80-20 rule", suggest? ASQ Quality Glossary, entry "Pareto chart"
  • What kind of work is DMAIC ideal for? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • Which Define-phase tool is used to understand what satisfies, delights and dissatisfies customers? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • Who is an external customer? ASQ Quality Glossary, entry "External customer"

Measure 13

  • A process mean sits exactly at the midpoint of the specification range. How do Cpk and Cp compare? NIST/SEMATECH e-Handbook of Statistical Methods, section 6.1.6, What is Process Capability
  • Complaint data are sorted by shift, by product line and by region before they are analyzed. What is this called? ASQ Quality Glossary, entry "Stratification"
  • Five delivery times are 3, 4, 5, 6 and 42 days. What are the mean and the median? NIST/SEMATECH e-Handbook of Statistical Methods, section 1.3.5.1, Measures of Location
  • In the name "Six Sigma", what is one sigma? ASQ Quality Glossary, entry "Sigma"
  • In which DMAIC phase is baseline performance established? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • The index Cp compares the tolerance with what? ASQ Quality Glossary, entry "Cp"
  • What does a capability analysis assess? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • What is a run chart? ASQ Quality Glossary, entry "Run chart"
  • What is accuracy in measurement? ASQ Quality Glossary, entry "Accuracy"
  • What is calibration? ASQ Quality Glossary, entry "Calibration"
  • Which control charts are based on variable, or measured, data? ASQ Quality Glossary, entry "Variable data"
  • Which Measure-phase tool records the activities that make up the process? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • Which of these can be read from a histogram? NIST/SEMATECH e-Handbook of Statistical Methods, section 1.3.3.14, Histogram

Analyze 13

  • A sampling plan accepts a lot that is in fact unacceptable. Which error is this? ASQ Quality Glossary, entry "Type II error"
  • A team faces many problems at once and wants to focus on the most significant. Which chart is recommended? ASQ Quality Resources, "Pareto Chart"
  • A team has found the root cause of a defect. What does that achieve by itself? ASQ Quality Resources, "Root Cause Analysis"
  • Call-handling times differ a little from call to call, with no single reason behind any one of them. What kind of cause is at work? ASQ Quality Glossary, entry "Common causes"
  • The five whys drill down into a problem. What are the five hows used for? ASQ Quality Resources, "Five Whys and Five Hows"
  • How does a fishbone diagram help a team find the causes of a problem? ASQ Quality Resources, "Fishbone Diagram"
  • In a statistical test, what is the null hypothesis? NIST/SEMATECH e-Handbook of Statistical Methods, section 7.1.3, What are statistical tests
  • In failure mode and effects analysis, what is a "failure mode"? ASQ Quality Resources, "Failure Mode and Effects Analysis (FMEA)"
  • In which DMAIC phase are the root causes of variation and poor performance determined? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • On a scatter diagram, what suggests a stronger relationship between the two variables? ASQ Quality Resources, "Scatter Diagram"
  • What does a t-test assess? ASQ Quality Glossary, entry "T-test"
  • What does analysis of variance (ANOVA) do with the total variation in a set of data? ASQ Quality Glossary, entry "Analysis of variance (ANOVA)"
  • When in the life of a product does FMEA have the most leverage? ASQ Quality Resources, "Failure Mode and Effects Analysis (FMEA)"

Improve 13

  • A form is redesigned so that the correct entry is far easier to make than a wrong one. Which mistake-proofing approach is this? ASQ Quality Resources, "Mistake Proofing"
  • A kaizen event is an intense run through the DMAIC process. About how long does it typically take? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • Continuous improvement can be incremental, a little at a time. What is the other form called? ASQ Quality Resources, "Continuous Improvement"
  • How often is the plan-do-check-act cycle meant to be run? ASQ Quality Resources, "Plan-Do-Check-Act (PDCA) Cycle"
  • In 5S, what is done in shine (seiso)? ASQ Quality Resources, "What are the Five S's (5S) of Lean?"
  • In most kaizen events, what happens to the changes during the event and after it? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • In which DMAIC phase are potential solutions identified and evaluated, and the process optimized? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • On a value stream map, what is placed around an item that needs improvement? ASQ Quality Resources, "Value Stream Mapping"
  • What can a designed experiment find that changing one factor at a time may miss? ASQ Quality Resources, "Design of Experiments"
  • What does quick changeover make possible? ASQ Quality Glossary, entry "Quick changeover"
  • What is design of experiments? ASQ Quality Glossary, entry "Design of experiments (DoE)"
  • Which kind of inspection checks, before a process step, that conditions are right? ASQ Quality Resources, "Mistake Proofing"
  • Which of these is another name for the plan-do-check-act cycle? ASQ Quality Resources, "Plan-Do-Check-Act (PDCA) Cycle"

Control 13

  • A capability estimate was made when the project began. When is it typically made again, and why? ASQ Quality Resources, "Process Capability"
  • A chart shows the process is out of control. What does the process engineer follow to look for an assignable cause? NIST/SEMATECH e-Handbook of Statistical Methods, section 6.1.4, What to do if the process is "Out of Control"
  • A customer audits one of its suppliers. What kind of audit is this? ASQ Quality Resources, "Auditing"
  • A new control chart was started while the process may have been out of control. When should its limits be recalculated? ASQ Quality Resources, "Control Chart"
  • For a normal distribution, what is the probability of a point falling outside plus or minus 3 sigma? NIST/SEMATECH e-Handbook of Statistical Methods, section 6.3.2, What are Variables Control Charts
  • In statistical process control, what does special cause variation indicate? ASQ Quality Resources, "Statistical Process Control"
  • Six points in a row each lie higher than the one before, all inside the control limits. What do the trend rules say? NIST/SEMATECH e-Handbook of Statistical Methods, section 6.3.2, What are Variables Control Charts
  • To what can the variation of an in-control process be attributed? ASQ Quality Glossary, entry "In-control process"
  • What are visual controls for? ASQ Quality Glossary, entry "Visual controls"
  • Where do the initial control limits of a chart come from? NIST/SEMATECH e-Handbook of Statistical Methods, section 6.1.2, What are Process Control Techniques
  • Which Control-phase tool is used to monitor process behavior? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • Which lean tool is listed for the Control phase, to make a workplace fit for visual control? ASQ Quality Resources, "The Define, Measure, Analyze, Improve, Control (DMAIC) Process"
  • Which lines does a control chart carry besides the plotted values? ASQ Quality Glossary, entry "Control chart"

How this list was compiled: Our own questions on the ground the three belt outlines share: lean, and the Define, Measure, Analyze, Improve and Control phases. The outlines are the Certified Six Sigma Yellow Belt, Green Belt and Black Belt bodies of knowledge (2022) that ASQ publishes (https://www.asq.org/cert/resource/pdf/certification/cssyb-cert-insert.pdf, https://www.asq.org/cert/resource/pdf/certification/cssgb-cert-insert.pdf, https://www.asq.org/cert/resource/pdf/certification/cssbb-cert-insert.pdf). Facts were read in ASQ's Quality Resources pages and Quality Glossary (asq.org/quality-resources) and in the NIST/SEMATECH e-Handbook of Statistical Methods (itl.nist.gov/div898/handbook), all on 2026-10-07. Each question names the page, entry or section it was written from. Licence: Own work. Every question, answer choice and explanation was written for this site from the public sources named on it. Nothing is taken from the exam, from its owner's question bank, study guide, handbook or courses, or from another practice test.

How it works

This Lean Six Sigma practice test covers the ground the yellow, green and black belts share. It is unofficial and not affiliated with, endorsed by or sponsored by ASQ (the American Society for Quality) or any other certifying body.

Read the full guide

Lean first, then the five phases

Lean drives out waste and Six Sigma reduces variation. The bank opens with 15 questions on lean and on the two together, then gives 13 to each phase of DMAIC: Define, Measure, Analyze, Improve and Control.

Which belt to practice next

Lean Six Sigma is not a single exam. For a belt exam, move to the page written to that belt's outline: the Yellow Belt practice test for roles and basic tools, or the Black Belt practice test for designed experiments and worked statistics.

  • Remember the eight wastes by the word DOWNTIME: defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, extra-processing.
  • For a "which phase" question, ask what the team holds: a charter, a baseline, a root cause, a tested solution or a control plan.

Questions and answers

How many questions are on a Lean Six Sigma exam?

It depends on the body and the belt. ASQ's computer-delivered exams score 80 questions for the Yellow Belt, 100 for the Green Belt and 150 for the Black Belt, each with unscored questions added. Other bodies set their own lengths.

Is Lean Six Sigma the same as Six Sigma?

Not quite. Lean focuses on waste reduction and Six Sigma on variation reduction. The combined name is used because process improvement often needs both, and ASQ's Six Sigma belt outlines include lean topics.

Is this Six Sigma practice test free?

Yes, and there is no sign-up. Answers are kept in your own browser and sent nowhere. Every question was written for this page; none comes from a certification exam or from another practice site.

What is DMAIC?

Define, measure, analyze, improve and control: a data-driven strategy for improving an existing process. Each phase has its own tools, and the questions on this page are sorted by those five phases.

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