Six Sigma Interview Questions & Answers

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Six-Sigma-Interview QA


Six Sigma (6σ) is a set of techniques and tools for process improvement. This data-driven and disciplined methodology can be used in any processes from manufacturing to transactional and from product to service. It was first introduced by Bill Smith while he was working in Motorola in 1986 and over the years it has gained popularity in different industries and sectors for business improvement.

There are a lot of advantages in using Six Sigma and its positive effects have been the driving force in the effective functioning of many businesses. This is the reason why Six Sigma professionals are still in great demand in various industries. If you are appearing for a Six Sigma job interview, the following commonly asked questions (with answers) will help you to be well prepared.

Here is the top list of Six Sigma Interview Questions and Answers that should be in your to do list before appearing for six sigma interview.


Q1. What is meant by COPQ in Six Sigma?


Cost of Poor Quality (COPQ) is the cost caused through producing defects.


Q2. What is the definition of DPMO or DPPM?


DPMO is Defects Per Million Opportunities and DPPM is Defective Parts Per Million


Q3. What is Pareto Principle?


The Pareto principle (or the 80/20 Rule) states that, for many events, roughly 80% of the effects come from 20% of the causes


Q4. Name some of the Quality Management tools in Six Sigma


There are a number of quality management tools. Some of them are cost-benefit analysis, CTQ Tree, SIPOC analysis, COPIS analysis, and Taguchi methods. (Name at least five)


Q5. Name the different kinds of variations used in Six Sigma?


The different kinds of variation are — mean, median, range and mode.


Also Read>>How Six Sigma Certification Has Become a Key Requirement!!


Q6. Who forms the part of Six Sigma implementation team?


The Six Sigma implementation team usually consists of the following members:

  1. Six Sigma Deployment Leader
  2. Six Sigma Champion
  3. Six Sigma Master Black Belt (MBB)
  4. Six Sigma Black Belt (BB)
  5. Six Sigma Green Belt (GB)
  6. Six Sigma Yellow Belt (YB)


Q7. What is the difference between the Six Sigma DMAIC and DMADV methodologies?


The DMAIC methodology, instead of the DMADV methodology, should be used when a product or process is in existence at your company but is not meeting customer specification or is not performing adequately.

The DMADV methodology, instead of the DMAIC methodology, should be used when:

  • A product or process is not in existence at your company and one needs to be developed
  • The existing product or process exists and has been optimized (using either DMAIC or not) and still does not meet the level of customer specification or Six Sigma level


Q8. Can you explain the concept of fish bone/ Ishikawa diagram?


It is a visualization tool for categorizing the potential causes of a problem in order to identify its root causes.



Q9. What is load testing process?


It is the process of putting demand on a software system or computing device and measuring its process


Q10. What level of understanding do you have regarding the statistical tools?


This should reflect the skills that you have regarding the statistical tools with respect to Six Sigma. Be honest while answering the question.


Q11. What is the difference between Cpk and Ppk?


Cpk is process capability index, which measures how close a process is running to its specification limits, relative to the natural variability of the process and Ppk is process performance index, which verifies if the sample that have been generated from the process is capable of meeting Customer CTQs (requirements).


Also Read>> Which is Better — Lean, Six Sigma or Both?


Q12. Can you explain standard deviation?


Standard deviation indicates the degree of variation in a set of measurements or a process by measuring the average spread of data around the mean.


Q13. What is process sigma calculation?


Process sigma is a measure of the variation in a process relative to customer requirements.


Q14. What is the 1.5 sigma shift?


The 1.5 sigma shift adjustment takes into account what happens to every process over many cycles of manufacturing.


Q15. What is Regression? When is it used?


Regression Analysis is a technique used to define relationship between an output variable and a set of input variables.

There are several types of regression like Simple Linear Regression, Multiple Linear Regression, Curvilinear Regression, Logit Regression and Probit Regression etc., which caters to a variety of requirements based on the type of underlying data.


Q16. What is the difference between defect and defective?


A defect is any non-conformance of the unit of product with the specified requirements. A defective is a unit of product which contains one or more defects.


Q17. What is the difference between Process Report and Product Report?


Process Report is used with continuous data that follow a bell curve distribution, while Product Report applies to discrete data and therefore can be used for all type of distributions.


Q18. Explain FMEA


FMEA is a qualitative and systematic tool, usually created within a spreadsheet, to help practitioners anticipate what might go wrong with a product or process.


Q19. What are X bar and R charts?


They are a set of two charts, which is the most commonly used statistical process control procedure used to monitor process behavior and outcome over time.


Q20. Explain Flow charting and brain storming?


A flowchart is a diagram displaying the sequential steps of an event, process, or workflow. Brainstorming is a technique used to quickly generate creative or original ideas on or about a process, problem, product, or service.

These are some of the popular questions that are asked in Six Sigma interviews. Always be prepared to answer all types of questions — technical skills, interpersonal, or methodology. Being prepared and practice are the ways you can be successful in a Six Sigma job interview.

About the Author

Hasibuddin Ahmed

Hasibuddin Ahmed

Hasib is a professional writer associated with He has written a number of articles related to technology, marketing, and career on various blogs and websites. As an amateur career guru, he often imparts nuggets of knowledge related to leadership and motivation. He is also an avid reader and passionate about the beautiful game of football.