Free The ASQ Certified Six Sigma Green Belt Practice Questions

Sample Practice Questions

Try these 10 sample questions from the The ASQ Certified Six Sigma Green Belt practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What is the principal mechanism by which Six Sigma seeks to improve customer satisfaction?

   1. A. Increasing finished-product inspection frequency
   2. B. Reducing process variation that leads to defects
   3. C. Increasing production batch sizes to reduce setups
   4. D. Expanding product variety to increase market share

   Answer: B

   Explanation: ASQ identifies the goal as "reducing and eliminating process variation that may lead to defects and/or errors/mistakes." This targets the variation causing unsatisfactory outputs.

   Reference: Six Sigma — ASQ — Overview

2. 2An existing process repeatedly misses customer performance requirements, and the causes are not established. Why is DMAIC an appropriate improvement approach?

   1. A. It systematically investigates and improves an existing process that falls short of requirements
   2. B. It starts by designing a replacement process before measuring the existing performance gap
   3. C. It selects a preferred solution before analyzing the factors responsible for the performance gap
   4. D. It limits improvement to screening finished outputs without changing the underlying process

   Answer: A

   Explanation: ASQ describes DMAIC as used to "improve existing processes that don’t meet performance standards or customer expectations." The existing performance problem fits that purpose; its Measure and Analyze phases precede choosing and implementing improvements.

   Reference: DMAIC Process — ASQ — Overview

3. 3A flowchart must branch according to whether an application is complete. Which symbol should contain that question?

   1. A. A process rectangle
   2. B. A document symbol
   3. C. A start/end symbol
   4. D. A decision diamond

   Answer: D

   Explanation: ASQ describes a "Decision based on a question" and says it is written in the diamond. A yes/no completeness test creates alternative flow paths.

   Reference: What Is a Flowchart? — ASQ — Commonly Used Symbols — decision

4. 4A team wants a preliminary graphical study of how diameter varies across machine, cavity position, and production cycle. Which analysis is designed to show relationships between factors and a response?

   1. A. A normal probability plot
   2. B. A gage bias plot
   3. C. A multi-vari chart
   4. D. A cumulative frequency plot

   Answer: C

   Explanation: Minitab says a multi-vari chart provides a "graphical representation of the relationships between factors and a response." It supports preliminary investigation of these grouped sources of variation.

   Reference: Overview for Multi-Vari Chart — Minitab — Overview — purpose

5. 5In a curing experiment, the investigator deliberately changes oven temperature to examine its effect on hardness. What DOE role does temperature have?

   1. A. Response
   2. B. Residual
   3. C. Factor
   4. D. Replicate

   Answer: C

   Explanation: NIST defines factors as "Process inputs an investigator manipulates to cause a change in the output." Temperature is the manipulated input.

   Reference: NIST/SEMATECH e-Handbook: A Glossary of DOE Terminology — Factors

6. 6How does common-cause variation differ from special-cause variation?

   1. A. Common causes are natural to the process; special causes arise from unusual occurrences
   2. B. Common causes always violate specifications; special causes always meet specifications
   3. C. Common causes affect only averages; special causes affect only ranges
   4. D. Common causes require a machine failure; special causes are ordinary process noise

   Answer: A

   Explanation: Minitab calls common-cause variation "natural or expected variation" and special-cause variation unexpected variation from unusual occurrences. These categories do not depend on specification conformance alone.

   Reference: Common-Cause and Special-Cause Variation — Minitab — What are common-cause variation and special-cause variation?

7. 7How does the Six Sigma improvement philosophy rank defect prevention relative to defect detection?

   1. A. Detection is preferred because defects supply improvement data
   2. B. Both are interchangeable ways to eliminate process causes
   3. C. Prevention is preferred over detecting defects after occurrence
   4. D. Detection is preferred until customer complaints increase

   Answer: C

   Explanation: ASQ describes a philosophy that "values defect/error prevention over defect/error detection." Detecting an existing defect does not itself prevent recurrence.

   Reference: Six Sigma — ASQ — Definition of Six Sigma

8. 8What establishes the boundaries of a process in a SIPOC analysis?

   1. A. The highest and lowest observed output values
   2. B. The start and end points of the process under study
   3. C. The budget and staffing levels of the process owner
   4. D. The suppliers' and customers' organizational reporting levels

   Answer: B

   Explanation: ASQ defines process boundaries as "the start and end points". These delimit the analysis rather than specifying performance, resources, or reporting structure.

   Reference: SIPOC+CM Diagram — ASQ — SIPOC+CM Diagram Procedure — identify process boundaries

9. 9In a process flowchart, what do arrows connecting its steps represent?

   1. A. The strength of statistical association between the steps
   2. B. The direction of flow from one step or decision to another
   3. C. The relative cost of completing each pair of activities
   4. D. The priority ranking assigned to each process participant

   Answer: B

   Explanation: ASQ defines the arrow meaning as "Direction of flow from one step or decision to another." It is a sequencing connection rather than a cost, rank, or correlation.

   Reference: What Is a Flowchart? — ASQ — Commonly Used Symbols — arrows

10. 10What summary does a standard Minitab multi-vari chart display at the levels of each factor?

    1. A. The response means
    2. B. Only the response variances
    3. C. Only the response ranges
    4. D. The factor-level p-values

    Answer: A

    Explanation: Minitab states, "The multi-vari chart displays the means at each factor level for every factor." It does not substitute a formal significance test for those graphical means.

    Reference: Overview for Multi-Vari Chart — Minitab — Overview — displayed statistic