Six Sigma Interview Questions

Last updated on Nov 21, 2023

Six Sigma is a series of management methods and strategies to reduce the risk of errors in the workplace. It's a data-driven tool for detecting and mitigating defects that employs a statistical technique. Six Sigma is a methodology that gives businesses the tools they need to develop their business processes. This enhancement in efficiency and reduction in process variance tends to reduce defects and boost earnings, employee productivity, and product or service quality." Six Sigma quality" means a word that means a well-controlled process.
In this article, you can go through the set of Six Sigma interview questions most  requently asked in the interview panel. This will help you crack the interview as the topmost industry experts curate these at HKR training.
Let us have a quick review of the Six Sigma interview questions.

Most Frequently Asked Six Sigma Interview Questions

    1. Six Sigma Interview Questions for Basic Level
    2. Six Sigma Interview Questions for Intermediate Level
    3. Six Sigma Interview Questions for Advanced Level

Six Sigma Interview Questions for Basic Level

Explain Six Sigma?

Ans:Sigma is a statistically based indicator of variance in a procedure. If the efficiency is 3.4 Defects per Million Opportunities (DPMO), the Six Sigma procedure is used. Six Sigma is a technique for resolving problems. This approach can be applied to a framework for identifying and removing the root cause of defects and the costs associated with them.

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Explain Six Sigma Levels?

Ans:It is a technique and collection of methods for assessing the consistency of an operation. It shows how effectively the business operation is managed. When the process's accuracy is less than 3.4 defects per million opportunities, you have reached the Six Sigma mark.

The number of defects per million that are appropriate for each Sigma standard is listed below:

Sigma level Defects per million opportunities

  • 690,000
  • 308,537
  • 66,807
  • 6,210
  • 233
  • 3.4

What are the different variations that are used in the Six Sigma process?

Ans: The various types of variations used in the six sigma method are as follows:

Mean: This calculation is only taken into account for a specific application, and the results are measured. So, in this method, the differences are calculated and compared using standard mathematical techniques.

Median: This procedure begins with determining the highest and lowest values, then dividing the result by two. The variations are evaluated and compared in this method by taking the midpoint of the data set collection.

Range: As the name suggests, it considers the highest and lowest rates for a given date range.

Mode: The most frequently occurring values in a given data set spectrum are known as a mode.

What are the different six sigma methodologies available?

Ans: The following are two six sigma sub methodologies that the teams should concentrate on:

  • DMAIC: It stands for ( Define, Measure, Analyze, Improve, Control)
  • DMADV: It stands for ( Define, Measure, Analyze, Design, Verify)

What is COPQ?


  • Cost of production quantity
  • Cost of poor quality
  • Cost of production quality
  • Cost of Poor quantity

If a product is not made to the highest standard, it incurs the expense of low production. If all of the systems and products produced are ideal, the COPQ will disappear.

What are the three key elements for six sigma process improvement?

Ans: The three critical elements for six sigma process improvement are as follows:

Customers: We must specify all possible metrics so that attributes such as on-time delivery, customer satisfaction, pricing, service, and transaction processing operations are crystal clear. It is crucial, and one must ensure that it is taken care of.

Process: This is a crucial part of implementing the Six Sigma method. Any customer will seek out a high-quality product. As six sigma process implementers, we must take special care to consider the process from the consumer's viewpoint.

Employees: Finally, to have a stable six sigma process execution, all company employees must be included and given the ability to develop their skill set.

Which of the following tools helps in visualizing series of causes to an effect?


  • Cause and Effect Matrix
  • Correlation Diagram
  • Ishikawa Diagram
  • Value Stream Mapping

The Ishikawa diagram, also known as the fishbone diagram, aids in the visualization of several possible causes for a given problem.

Name some Lean Six Sigma tools.

Ans: Some Lean Six Sigma tools are:

  • Kaizen.
  • Poka-yoke.
  • FMEA.
  • Value Stream Mapping.

Which analysis helps to prioritize customer requirements?


  • Kaizen
  • Kano
  • Control charts
  • Poisson

When consumer needs are known, Kano analysis may help prioritise them. In six sigma, Kano analysis is used to describe the DMAIC step.

. What is the difference between Cpk and Ppk?

Ans:Process capability index is abbreviated as Cpk. It determines how close a process is to meeting the design limits in comparison to the process' normal variability.

Ppk, on the other hand, is a process performance index that determines whether or not the sample provided by the process is capable of meeting Customer CTQs.

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Six Sigma Interview Questions for Intermediate Level

. Which of the following tasks should a Green Belt execute first in a standard Measure Phase?


  • Stability
  • Capability
  • MSA
  • Normality

There is more numeric and data analysis in the measured process. The MSA (measurement system analysis) can determine how much variance in the data the measuring system has produced. MSA is a time-consuming process.

. Explain what you mean by FEMA?

Ans: The term FEMA refers to the Measure Phase's final segment.

So, in a nutshell, it promotes the cause of avoiding defects from occurring in the first place. So, in a way, being cautious and ensuring that the process is free of known defects.

The probable defects are usually included in the FEMA process and are rated in three different ways:

  • The possibility that something would go wrong.
  • The potential to identify a defect.
  • Severity of the defect

If the defect severity is deemed minimal, the user may not need to spend any time validating the procedure.

. What is the main difference between Lean and Six Sigma?


To minimise waste, Six Sigma employs the DMAIC approach. Lean, on the other hand, employs the following seven steps:

  1. Overproduction: This happens when products are created but there is no one to purchase them.
  2. Waiting: There is little value added to the project if there is a time gap in and phase of production.
  3. Transport: When products are shipped in an inefficient manner, this occurs.
  4. Motion: This one refers to poor professional ethics and workers engaging in inefficient practises in between tasks.
  5. Over-processing: When you take too long to create a product, this happens.
  6. Inventory: This type of waste happens when the inventory volume is too high and you have too much work in progress.
  7. Defects: This is the amount of time workers spent finding and correcting production errors.

. What is the difference between load test and performance testing?

Ans: The following is the distinction between load testing and performance testing:

Load Testing:

Load testing is simply a phase in which the load limit exceeds the client's requirements.This will help us figure out whether the program can support a certain amount of data.
Load checking determines how well an application or service behaves and how many concurrent users can log in without experiencing any issues.
Performance Testing:

Performance testing entails putting more emphasis on system tests as well as the overall programme and system performance under stress. Performance testing is, in several ways, a subset of load testing.
Load and stress testing are also part of the performance testing process.

. Explain what is meant by Lean Six Sigma?

Ans: A lean six sigma approach, on the other hand, is a methodology that entails the whole team's commitment to bring about progress in terms of efficiency enhancement by finding waste and reducing variation.

As a result, they work in conjunction with the lean six sigma method to remove eight different types of waste:

  • Defects
  • Overproduction
  • Transportation
  • Inventory
  • Motion
  • Extra Processing

These are only a few examples of areas where the process flow can be improved and optimised by improving the whole process flow.

. What are Function Points In Project Management?


A function point is a measuring unit used to express the amount of business functionality provided by an information system.

There is an association of consumers of software metrics called the International Function Point Users Group, which is headquartered in the United States. Analysis of Function Points The IFPUG practical size measuring system uses feature points as a unit of measurement.

The IFPUG FSM is one of the ISO specifications for technically sizing functionality that is currently in use.

. What is the main role of a Master black belt in terms of implementing a six sigma team?

Ans: The main role of Master black belt holder of the six sigma process is vital for an organization because most organizations don’t start with a concrete six sigma process. 

So building up the practice and making sure that they are in line with the standards is very important. So the core process is initiated and mentored if necessary to the users who are part of the six sigma process implementation team.

. What is the Top-down approach in the six sigma process?

Ans: One of the processes used in Six Sigma implementation is the top-down method. As a result, this practise is normally in accordance with the company's policy and consumer requirements.

However, one of the main drawbacks is that the variety is extremely wide, making it difficult to complete in a reasonable period of time.

Six sigma programs are usually finished in three to six months, according to industry guidelines.

. What are the three steps for Root cause analysis?

Ans: The three steps for Root cause analysis is:

Open step: This is the first move, in which all members of the team are assembled and a brainstorming session on all potential possibilities is held.

Narrow step: Considering our current sigma results, all potential theories and possibilities are narrowed down to some degree during this process.

Close step: During this process, the project team will confirm all of the reasons for the current sigma performance that have been narrowed down.

. Explain what is a Pareto principle?

Ans: The data is shown using a Pareto map, which is built on the Pareto principle's underlying definition. It's known as the 80/20 law.

Using this rule would allow the team to concentrate on individual projects and problems that could have a larger effect if not addressed early on.

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Six Sigma Interview Questions for Advanced Level

. When is the FMEA process generally performed?


  • Begin throughout the design concept stage and continue throughout the project.
  • After the production tool has been authorized.
  • It comes to an end as soon as the conceptualization is completed.
  • This was implemented in the design phase.

FMEA (failure mode and effect analysis) is a systemic method/approach for identifying potential failures in architecture, production or assembly processes, or a product or service. This procedure starts with the project's conception and continues throughout the project's lifecycle.

. What is a data collection plan?

Ans: A data collection plan is nothing more than a strategy for gathering the requisite information. As a result, the following areas are covered in this program.

  • The data collection strategy analyses the kind of data that needs to be processed or obtained.
  • What data sources are used to interpret the data in the data collection plan?

As a result, the primary goal of data collection is to get a better understanding of the present procedure and to depict potential improvements. The following are three main sources from which data can be gathered.

Input: The term "input" refers to the location where data is generated.

Process: The method is made up of implementation phases that take into account considerations such as performance, time constraints, expense, and defects to enhance the process.

Output: It's a straightforward productivity metric.

. When a cause-and-effect diagram is used to solve plant problems, what are the three parts a session is customarily divided into?


  • Teamwork, cost-effectiveness, efficiency
  • Brainstorming, prioritization and plan development
  • Teamwork, planning and execution
  • Cost-effectiveness, plan development, teamwork.

A cause and effect diagram helps to identify the possible causes and the outcomes of a problem. This is done is three parts; Brainstorming, prioritization and plan development

. How to develop a SIPOC process map?

Ans: SIPOC stands for Suppliers Input Process Output Customers.

A process is a series of similar steps and tasks that are carried out in a logical order to produce a particular outcome.

The following elements must be identified using the SIPOC method map:

  • How are the current processes operating?
  • How are the processes modified and improved?
  • How is the improvement carried out or implemented with the next phases of DMAIC?

. Explain Key Roles In All Six Sigma Efforts ?


The following are the key roles of Six Sigma efforts:

Sponsor: The organisation is led by a business executive.

Champion: Responsible for Six Sigma strategy, deployment, and vision.

Process Owner: Responsible for long-term sustainability gains is the owner of the enhanced process, product, or service..

Master Black Belts: Coach black belts expert in all statistical tools.

Black Belts: Work on 3 to 5 $250,000-per-year projects; create $1 million per year in value.

Green Belts: Work with black belts on projects.

. How does the cost of six sigma implementation is estimated by the organizations?

Ans: The cost of implementing six sigma is calculated in a variety of ways, and a few of the more common ones are described below:

1. The cost of implementing six sigma should be deducted from the company's own payroll, and the people who worked full time on this process can be compensated accordingly.

2. This is an informal payroll policy in which people are classified and paid based on tasks such as data collection, measurements, and conversations with product owners, among other things.

3. This is purely a consultative approach, with consultants being compensated according to the amount of hours they spent training and mentoring the team.

4. This is an entirely new approach to the six-sigma methodology. The payoff can occur as a result of the improvisation process.

. A Six Sigma Green Belt practitioner constructs a control chart to display a process mean and its outer limits. In such a chart, what does UCL stand for?


  • Upper Cycle Length
  • Upper Control Limit
  • Upper Cycle Limit
  • Upper Control Length

Control charts are two-dimensional graphs that show data on the x-axis and time on the y-axis.Upper control limit (UCL), Lower control limit (LCL), and average or centre line of the data are the three characteristics of a control chart. A three-process control above the standard deviation is the upper control limit.

. For a process working at 5 Sigma level, how many opportunities are considered to lie outside of the specification limits provided by the customer?


  • 233
  • 6210
  • 3.4
  • 66807

The Sigma 4 standard refers to the average percentage of precision which shows the highest number of defects per million in a process or device. A 5 sigma level 233 errors per million.

. In the project development cycle, what would a “Waste” mean?


  • Time spent on unproductive events
  • Time spent on fixing defects
  • Time spent on Unproductive resources
  • Time spent on unnecessary expenditure

In lean, anything that does not contribute to the final product's functionality is referred to as "Waste." That is to say, the time spent correcting defects is called waste.

. What are the benefits of the six sigma process to the organization and for the individual practicing it?

Ans: The benefits of the six sigma process are as follows:

  • Aids the enterprise in reducing mistakes to the point that they can be eliminated.
  • Contributes to the improvement of business processes.
  • Contributes to the enhancement of Quality Assurance.
  • This process can be applied throughout the business environments, applicable for all the markets.
  • Ascertains that it is in compliance.
  • Individuals are assisted in developing expertise and becoming leaders.
  • Individuals with this experience should be compensated well.
  • Quality assurance and quality management.

. What are the popular myths or misunderstandings about the Six Sigma process?

Ans: The popular myths or misunderstanding about six sigma process is as follows:

  • Six Sigma is a method that focuses solely on defect reduction.
  • The Six Sigma method is used in the production and deployment of projects.
  • Six Sigma is merely a type of training with no practical implementation.
  • Engineering operations cannot be subjected to the Six Sigma process.

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About Author

As a Senior Writer for HKR Trainings, Sai Manikanth has a great understanding of today’s data-driven environment, which includes key aspects such as Business Intelligence and data management. He manages the task of creating great content in the areas of Digital Marketing, Content Management, Project Management & Methodologies, Product Lifecycle Management Tools. Connect with him on LinkedIn and Twitter.

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