35+ [REAL-TIME] Six Sigma Interview Questions & Answers
Last updated on 04th Jul 2020, Blog, Interview Questions
Six Sigma is a method that provides organizations tools to improve the capability of their business processes. This increase in performance and decrease in process variation helps lead to defect reduction and improvement in profits, employee morale, and quality of products or services.”Six Sigma quality” is a term generally used to indicate a process is well controlled (within process limits ±3s from the center line in a control chart, and requirements/tolerance limits ±6s from the center line).
1) Explain Six Sigma?
Ans:The measure of variation in a process which is statistical in nature is known as Sigma. The Six Sigma process is derived if the quality is 3.4 Defect per Million Opportunities (DPMO). Six Sigma is a problem solving methodology. This methodology is applicable to a process for eliminating the root cause of defects and the costs that are associated with the same.
2) Explain Six Sigma Levels?
Ans:It is a methodology and set of tools for the measurement of process quality. It demonstrates that the business process is well controlled. Six Sigma level can be achieved when the accuracy of your process gets only 3.4 defects per million opportunities.
Here’s the list of acceptable number of defects per million to correspond to each Sigma level:
Sigma level Defects per million opportunities
3) Explain The Different Kinds Of Variations Used In Six Sigma?
Ans:The following are the kids of variations used in SIX Sigma:
Mean: The variations are measured and compared using the averaging techniques of mathematics. The measures are taken for a specific application and the mean is calculated
Median: The variations are measured and compared using the mid point in a given range of data. It is measured by finding the highest and lowest value then dividing it by two. The lowest value is added to the same
Range: The values of a specific data range. It is the difference between highest and lowest values in a specific data range.
Mode: Mode is the most occurred values in a given data range.
4) Explain Six Sigma Variation Kinds?
Ans:Six Sigma aims to deliver quality products to the customers. It also intends to reduce output variation by predicting process results. Processes here would be measure, analyze, improve and control, Variation here means how much has the output deviated from the actual. Six sigma means as the process deviation increases the sigma number is decreased. Having the sigma number as 6 would mean that there will be no items that don’t meet with the specifications.
5) Explain The Different Kinds Of Variations?
Ans:Reduction variations is the strategy of Six Sigma approach. Standard deviation which is a square root of variance is the measure of variations. The approach is to reduce the sigma value and the better process experience.
However , there are two other types of variations, namely, Operator origin variations …measured as Reproducibility and Guage variations …repeatability is another element of Guage variations coming from operator origin.Measurement system analysis deals withis types of variations.
There is another aspect of looking at the multiple sample variations by way of ANOVA
6) Tell Me Who Forms The Part Of Six Sigma Implementation Team?
Ans:Six Sigma implementation team has five key players:
Master black belt
7) Explain Who Forms The Part Of Six Sigma Implementation Team?
Ans:Executive leaders: The decision of to six sigma is taken by the main team – Executive Leaders. They promote the six sigma throughout the enterprise and ensure the commitment of the enterprise in six sigma. The executive leaders are mainly CEO, or some of the board of directors. The six sigma initiative is funded by Executive leaders. The executive leaders should be confident and determine that six sigma will improve organization process and it is succeeded.
Champions: Champions are normally the senior manager of the enterprise. He promotes six sigma mainly among the users of the business. He acts as a coach, mentor, selects projects, decides the objectives, allocates the resources and removes hurdles from black belt players. The champions fight for removing black belt hurdles.
Master Black-Belt: This role highly demands the technical capability in six sigma. All organizations are not started with six sigma and will not have the same. Normally outsiders are recruited for it. The key role of Master Black-belt is train, mentor and guide. He supports the executive leaders in candidate’s selection; teach the fundamentals and train resources and right project for resources.
Black-Belt: Black-belt always leads a selected project team for show casing six sigma. Their responsibilities include finding out the variations and looking after minimizing the variations. Black belt normally selects the projects, train resources, and they are the real implementers of the project. They are the core resources to six sigma as the actual implementation of six sigma is done by black belt, in the enterprise.
Green Belt: The green belt resources supports black belt in the functionality areas. They are part time resources who work mainly on projects for six sigma implementation. The six sigma methodologies for solving problems are applied by green belt and help for defining the basic six sigma implementation of the enterprise. The too support black belt in implementing six sigma in the enterprise.
8) Explain The Six Sigma Implementation Team?
Ans:Attaining Six Sigma is a team effort. An organization who wants to attain Six Sigma needs a lot of restructuring and change in attitude. It includes building up the following roles to take up the required responsibilities:
- Executive Leadership-Includes CEO and other top management team members. They set up the vision of Six Sigma and empower their team mates with the freedom and resources required for the improvements in the process.
- Champions- Responsible for the implementation of the process in an integrated manner throughout the organization. They come from Top management.
- Master Black Belts-Act as in-house expert coach for the organization. They assist Champions and train Black Belts and Green Belts.
- Black Belts-Apply Six Sigma methodology to specific projects. Their focus is on execution of activities for Six Sigma.
- Green Belts-These are like the soldiers on the war front who actually implement the planned action.
9) What Are Function Points In Project Management?
Ans:In order to express the amount of business functionality of an information system, a function point is used as a unit of measurement.
There is International Function Point Users Group in US based organization of users of the software metric Function Point Analysis Every function point is a unit of measure used by IFPUG functional size measurement method.
The IFPUG FSM is one of the currently recognized standards of ISO for functionally sizing software.
10) What Is Six Sigma Dmaic?
Ans:The DMAIC project methodology has five phases:
Define the problem, the voice of the customer, and the project goals, specifically. Measure key aspects of the current process and collect relevant data. Analyze the data to investigate and verify cause-and-effect relationships. Determine what the relationships are, and attempt to ensure that all factors have been considered. Seek out root cause of the defect under investigation.
Improve or optimize the current process based upon data analysis using techniques such as design of experiments, poka yoke or mistake proofing, and standard work to create a new, future state process. Set up pilot runs to establish process capability.
Control the future state process to ensure that any deviations from target are corrected before they result in defects. Implement control systems such as statistical process control, production boards, visual workplaces, and continuously monitor the process.
11) What Are Quality Management Tools And Methods Used In Six Sigma?
Ans:Within the individual phases of a DMAIC or DMADV project, Six Sigma utilizes many established quality-management tools that are also used outside Six Sigma.
12) When And By Whom Was Six Sigma Developed ?
Ans:In 1986 Six Sigma was developed by Motorola.
13) What Is The Symbol Of Six Sigma ?
Ans:Six Sigma has a greek symbol which is ”sigma”. It is the standard deviation utilized to measure the variation in the process.
14) Six Sigma Uses Two Key Methods. What Are They?
Ans:They are DMAIC and DMADV
15) What Does Dmaic Stands For In Six Sigma ?
Ans:DMAIC is an abbreviation for define, measure, analyze, improve and control.
16) What Does Dmadv Stands For In Six Sigma ?
Ans:DMADV is an abbreviation for define, measure, analyze, develop, verify.
17) Have You Seen Six Sigma Jobs Being Advertised Under Many Titles ?
Ans:Six Sigma jobs are advertised under many titles,not always as obvious as Six Sigma Black Belt,Six Sigma Consultant or Six Sigma Analyst.Other possible titles include things like Functional Project Lead Six Sigma Program Manager,Lead Analyst/Project Manager,Director of Operational Excellence, Business Process Manager or Senior Projects Manager.Whatever the exact title, the organization is looking for someone with the skills of a Six Sigma Black Belt.
18) Explain Scope Of Your Future In Six Sigma Type Job ?
Ans:You need to be able to demonstrate a good understanding of processes and quality methodologies and a willingness to take an initiative and lead change. Another crucial skill is the ability to link strategy to execution.
19) Explain The Quality Levels Of Six Sigma ?
Ans:Six Sigma quality levels are 99.9996% accurate and also they have only 3.4 defects per million opportunities.
20) Explain Key Roles In All Six Sigma Efforts ?
Ans:The following are the key roles of Six Sigma efforts:
Sponsor: Business executive leading the organization.
Champion: Responsible for Six Sigma strategy, deployment, and vision.
Process Owner: Owner of the process, product, or service being improved responsible for long-term sustainable gains.
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 belt on projects.
21) Explain Maic In Six Sigma ?
Ans:The following explains the MAIC :
Measure: Problem assessment by gathering right information.
Analyze: Identify root cause of problem by using statistical tools.
Improve: Solve the problem (not the symptom).
Control: Put a plan in place to make a check that problems stay fixed and sustain the gains.
22) How Should Company Integrate Lean Into Six Sigma ?
Ans:Lean takes the waste out of an area six sigma resolves the issue
23) Differentiate Between Load Test And Performance Testing?
Ans:More stress is involved in performance testing, on system and checks whether the system performance is same as the less stress condition. Where as in load testing the stress is kept beyond the limit specified by the client.Performance testing is the super set of load testing. Load testing involves the testing process which determines how well the system is capable for handling concurrent users or the load. Where as performance testing includes the load as well as the stress testing.
24) Explain Load Testing Process ?
Ans:The following steps explains the Load testing process :
Plan the test. A clear test plan is required for ensuring the test scenarios to accomplish the objectives of load testing Creation of Vusers. Vusers scripts are created that contains the tasks performed by each and every Vuser and all Vuser tasks collectively as a whole.
Creation of scenario. Describing the events that occurred in the testing. This process includes the list machines, scripts, and Vusers which run during the scenario. The Load Runner controller is used for creation of automatic scenarios.
25) Mention The List Of Acceptable Number Of Defects Per Million Corresponding To Each Sigma Level ?
Ans:Following information mentions the acceptable number of defects per million to correspond to each Sigma level:
Sigma level Defects per million opportunities
- 1 690,000
26) Explain The Concept Of Standard Deviation?
Ans:Standard deviation quantifies the variation most accurately indicating the degree of variation in a set of measurement or a process by measuring the average spread of data around the mean. It provides accurate information
27) What are the different variations that are used in the Six Sigma process?
Ans:Mainly 4 variations are used in six sigma process:
Mean: This measurement is only useful for a particular application and the values are calculated. In this process, the variations are measured and compared using the average techniques of mathematics.
Median: This process is initiated by identifying the highest and the lowest values and then divide the value by 2. In this process, the variations are measured and compared by taking the midpoint the data set range.
Range: This process depends on the highest rate and lowest values for a specific data range.
Mode: Mode is the most occurred values in a given data set range.
28) What is the difference between the Six Sigma DMAIC and DMADV methodologies?
Ans:The DMAIC project methodology has five phases:
- Define the system, the voice of the customer and their requirements, and the project goals, specifically.
- Measure key aspects of the current process and collect relevant data; calculate the ‘as-is’ Process Capability.
- Analyze the data to investigate and verify cause-and-effect relationships. Determine what the relationships are, and attempt to ensure that all factors have been considered. Seek out the root cause of the defect under investigation.
- Improve or optimize the current process based upon data analysis using techniques such as the design of experiments, poka-yoke or mistake proofing, and standard work to create a new, future state process. Set up pilot runs to establish process capability.
- Control the future state process to ensure that any deviations from the target are corrected before they result in defects. Implement control systems such as statistical process control, production boards, visual workplaces, and continuously monitor the process. This process is repeated until the desired quality is achieved.
On the other hand, DMADV methodologies five phases are:
- Define design goals that are consistent with customer demands and the enterprise strategy.
- Measure and identify CTQs (characteristics that are Critical To Quality), measure product capabilities, production process capability, and measure risks.
- Analyze to develop and design alternatives
- Design an improved alternative, best suited per analysis in the previous step
- Verify the design, set up pilot runs, implement the production process and hand it over to the process owner(s).
29) Explain the concept of the Fishbone diagram.
Ans:Fishbone or Ishikawa diagram is a visualization tool for categorizing the potential causes of a problem in order to identify its root causes.
30) What is the load testing process?
Ans:The load testing process is a process of putting your demand on a software system or computing and measuring its process.
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31) What is the difference between load test and performance testing?
Ans:Performance Testing is a type of software testing that can be carried out to measure the system performance in terms of sensitivity, reactivity, and stability under a particular workload.
On the other hand, The load testing process is a process of putting your demand on a software system or computing and measuring its process.
32) What are the three key elements for the six sigma process improvement?
Ans:The 3 key elements for the six sigma process improvement are customer, process, and employees.
33) What is a Top-down approach in the six sigma process?
Ans:The top-down approach is one of the processes within the Six Sigma implementation. This approach is aligned with business strategy and customer needs. Although, the major disadvantage of this process is its scope is very broad and at the same time it is difficult to execute it in a specified amount of time.
34) Explain what do you mean by FMEA?
Ans:FMEA is an acronym for Failure Modes and Effect Analysis. FMEA is a risk assessment tool, that evaluates the severity, occurrence, and detection of risks to prioritize the most urgent ones.
35) What are the three steps for Root cause analysis?
Ans:The 3 steps for Root cause analysis are:
- The Open step: In this step, all the team members gather together and do a brainstorming session on all possible scenarios.
- The Narrow step: They narrow down all the possible explanations and scenarios are to an extent considering the current performance.
- The close step: The project team validates all the narrowed down explanations for the current performance.
36) What is the main difference between Lean and Six Sigma?
Ans:Six Sigma follows the DMAIC methodology to reduce waste. On the other hand, Lean uses these following 7 steps:
- Overproduction: This occurs when products are being produced but there is no customer to demand it.
- Waiting: If there is a time lag after every step of production, no value is being to the project in the meantime.
- Transport: This happens when products are being moved in an inefficient way.
- Motion: This one denotes poor work standards and employees being involved in inefficient activities between tasks.
- Over-processing: This takes place when you spend too much time in producing a product.
- Inventory: When your inventory level is too high and you have too much work in progress, this kind of waste takes place.
- Defects: This is the number of times when employees spend identifying and fixing production mistakes.
37) What is Lean Six Sigma?
Ans:Lean Six Sigma is a method that relies on a collaborative team effort to improve performance by systematically removing waste and reducing variation. It combines lean manufacturing/lean enterprise and Six Sigma to eliminate the eight kinds of waste: Defects, Over-Production, Waiting, Non-Utilized Talent, Transportation, Inventory, Motion, and Extra-Processing.
38) What is the difference between Cpk and Ppk?
Ans:Cpk stands for process capability index. It measures how close a process is running to its specification limits, relative to the natural variability of the process.
On the other hand, Ppk stands for a process performance index that verifies if the sample has been generated from the process is capable of meeting Customer CTQs or not.
39) Name some Lean Six Sigma tools.
Ans:Some Lean Six Sigma tools are:
- Value Stream Mapping
40) What does DFSS stand for in the six sigma process?
Ans:DFSS stands for Design For Six Sigma. It is a business process management method related to traditional Six Sigma and is used in many industries, like finance, marketing, basic engineering, process industries, waste management, and electronics.
41) What is a data collection plan?
Ans:A data collection plan a plan to collect the necessary data. The main reason to collect data is to understand the current process and portray possible improvement suggestions. The data can be collected from three different primary sources they are as follows:
- Input: input is where the data generation.
- Process: the process is the execution steps where the factors like efficiency, time requirements, cost, defects are taken into consideration for process improvements.
- Output: it is a straight measurement of efficiency.
42) Explain the difference between a Histogram and a Boxplot.
Ans:A Histogram represents the frequency distribution of numeric data, while a Boxplot summarizes the important aspects of continuous data distribution.
43) What is VSM?
Ans:VSM stands for Value Stream Mapping. This is a methodology used to eliminate wastes from a process and map the flow of information required to deliver a product or service.
44) What is MSA?
Ans:MSA stands for Measurement System Analysis. One can use MSA to check if a measurement system is accurate. It evaluates a system’s accuracy, precision, and stability.
45) How to develop a SIPOC process map?
Ans:SIPOC stands for Suppliers Input Process Output Customers.
It defines that a process can be summarized as a series of consecutive steps and activities that are executed in a timely manner to get a definite output.
46) Can you explain the different methodologies for execution and design process in Six Sigma?
Ans:The main focus of Six Sigma is on reducing defects and variations in the processes. DMAIC and DMADV are the models used in most Six Sigma initiatives. DMADV is a model for designing a process while DMAIC is for improving the process.
The DMADV model has the below five steps:
- Define: Determine the project goals and the requirements of customers (external and internal).
- Measure: Assess customer needs and specifications.
- Analyze: Examine process options to meet customer requirements.
- Design: Develop the process to meet customer requirements.
- Verify: Check the design to ensure that it’s meeting customer requirements.
DMAIC model has the below five steps:
- Define the projects, the goals, and the deliverables to customers (internal and external). Describe and quantify both the defect and the expected improvement.
- Measure the current performance of the process. Validate data to make sure it is credible and set the baselines.
- Analyze and determine the root cause(s) of the defects. Narrow the causal factors to the vital few.
- Improve the process to eliminate defects. Optimize the vital few and their interrelationships.
- Control the performance of the process. Lock down the gains.
Figure: Methodology in Six Sigma
Figure: DMAIC and DMADV
47) What does executive leaders, champions, Master Black belt, green belts and black belts mean?
Ans:Six Sigma is not only about techniques, tools, and statistics, but the main thing depends on people. In Six Sigma, there are five key players:
- Executive leaders
- Master black belt
- Black belts
- Green belts
Let’s try to understand all the roles of the players step by step.
- Executive leaders: They are the main people who actually decide that we need to do Six Sigma. They promote it throughout organization and ensure commitment of the organization in Six Sigma. Executive leaders are the guys who are mainly either CEO or from the board of directors. So in short they are the guys who fund the Six Sigma initiative. They should believe that Six Sigma will improve the organization process and that they will succeed. They should be determined that they ensure resources get proper training on Six Sigma, understand how it will benefit the organization, and track the metrics.
- Champions: Champion is a normally a senior manager of the company. He promotes Six Sigma mainly between business users. He understands Six Sigma thoroughly, serves as a coach and mentor, selects projects, decides objectives, dedicates resources to black belts, and removes obstacles which come across black belt players. Historically Champions always fight for a cause. In Six Sigma they fight to remove black belt hurdles.
- Master Black-Belt: This role requires the highest level of technical capability in Six Sigma. Normally organizations that are just starting up with Six Sigma will not have them. So normally outsiders are recruited for this. The main role of a Master Black belt is to train, mentor, and guide. He helps the executive leaders in selecting candidates, right projects, teach the basics, and train resources. They regularly meet with black belt and green belt training and mentor them.
- Black-Belt: Black belt leads a team on a selected project which has to be show-cased for Six Sigma. They are mainly responsible to find out variations and see how these variations can be minimized. Most black belts basically select a project and train resources, but black belts are the guys who actually implement it. Black belt normally works in projects as team leads or project managers. They are central to Six Sigma as they are actually implementing Six Sigma in the organization.
- Green Belt: Green belts assist black belts in their functional areas. They are mainly in projects and work part time on Six Sigma implementation. They apply Six Sigma methodologies to solve problems and improve a process at the bottom level. They have just enough knowledge of Six Sigma and they help define the base of the Six Sigma implementation in the organization. They assist black belts in the Six Sigma implementation actually.
Figure: Six key players
48) What are the different kinds of variations used in Six Sigma?
Ans:Variation is the basis of Six Sigma. It defines how much changes are happening in the output of a process. So if a process is improved then this should reduce variations. In Six Sigma we identify variations in the process, control them, and reduce or eliminate defects. Now let’s understand how we can measure variations.
There are four basic ways of measuring variations: Mean, Median, Mode, and Range. Let’s understand each of these variations in more depth for better analysis.
Figure: Different variations in Six Sigma
Mean: In mean the variations are measured and compared using math’s averaging techniques. For instance, you can see the below figure which shows two weekly measures of how many computers are manufactured. So for we have tracked two weeks, one we have named Week 1 and the other Week 2. So to calculate the variation by using mean we calculate the mean of week1 and week2. You can see from the calculations below we have got 5.083 for week1 and 2.85 for week2. So we have a variation of 2.23.
Figure: Measuring variations by using Mean
Median: Median value is a mid point in our range of data. Mid point can be found out by finding the difference between the highest and lowest value then dividing it by two and finally adding the lowest value to it. For instance, for the below figure in week1 we have 4 as the lowest value and 7 as the highest value. So first we subtract the lowest value from the highest value, i.e., 7 -4. Then we divide it by two and add the lowest value. So for week1 the median is 5.5 and for week2 the median is 2.9. So the variation is 5.5 – 2.9.
Figure: Median for calculating variations
Range: Range is nothing but a spread of values for a particular data range. In short it is the difference between the highest and lowest values in a particular data range. For instance you can see for the recorded computer data of two weeks, we have found out the range values by subtracting the highest value from the lowest.
Figure: Range for calculating variations
Mode: Mode is nothing but the most occurred values in a data range. For instance in our computer manufacturing, data range 4 is the most occurred value in Week1 and 3 is the most occurred value in week 2. So the variation is 1 between these data ranges.
Figure: Mode for calculating variations
49) Can you explain the concept of standard deviation?
Ans:The most accurate method of quantifying variation is by using standard deviation. It indicates the degree of variation in a set of measurements or a process by measuring the average spread of data around the mean. It’s but complicated than the deviation process discussed in the previous question, but it does give accurate information.
Note: To understand standard deviation we will be going through a bit of math so please co-operate and keep your head cool. In the below steps we will go step by step and understand how we can implement standard deviation.
Below is the formula for Standard Deviation. “σ“ symbol stands for standard deviation. X stands for observed values; X (with the top bar) is the arithmetic mean and n is the number of observations. The formulae must be looking complicated but let’s break them up in to steps and understand them better.
Figure: Standard deviation formulae
The first step is to calculate the mean. This can be calculated by adding all the observed values and dividing that by the number of observed values.
Figure: Step 1 Standard Deviation
The second step is to subtract the average from each observation, square them, and then sum them. Because we square them we will not get negative values. The below figure indicates the same in a very detail manner.
Figure: Step 2 Standard deviation
In the third step we divide the same with the number of observations, as shown the figure.
Figure: Step 3 Standard deviation
In the final step we take the square root which gives the standard deviation.
Figure: Step 4 standard deviation
Note: Below are some questions which we have not answered and have been left as an exercise to the readers. We will definitely try to cover that in the second edition.
50) Can you explain the concept of fish bone/ Ishikawa diagram?
Ans:There are situations where we need to analyze what caused a failure or problem in a project. Fish bone or Ishikawa diagram is one of the important concept which can help you list down your root cause of the problem. Fish bone was conceptualized by Ishikawa, so in the honor of its inventor this concept was named as Ishikawa diagram. Inputs to conduct a fish bone diagram comes from a discussion and brain storming with people who were involved in the project. The below figure shows how the structure of the Ishikawa diagram is. Below is a sample fish bone diagram. The main bone is the problem which we need to address and to know what caused the failure. For instance the below fish bone is constructed to know what caused the project failure. To know this cause we have taken four main bones as input: Finance, Process, People, and Tools. For instance, on the people front, there are many resignations, this was caused because there was no job satisfaction – this was caused because the project was a maintenance project. In the same way causes are analyzed on the Tools front also. In tools – No tools were used in the project – because no resource had enough knowledge about the same – this happened because of a lack of planning. In the process front, the process was adhoc – this was because of tight deadlines – this was caused because marketing people over promised and did not negotiate properly with the end customer.
Now once the diagram is drawn the end bones of the fish bone signify the main cause of the project failure. From the below diagram, here’s a list:
- No training was provided for the resources regarding tools.
- Marketing people over promised with customer which leads to tight deadlines.
- Resources resigned because it’s a maintenance project.
Figure: Fish bone / Ishikawa diagram
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51) What is Pareto principle?
Ans:Pareto principle, also paraphrased as 80/20 principle, is a simple and effective problem tackling way in management. It says that 20% of your problems lead to the other 80 % of problems. So rather than concentrating on the 80% of problems if you concentrate on 20% of problems you can save a lot of trouble. So in Pareto you analyze the problems and only concentrate on 20% of your vital problems.
If you look at the above fish bone diagram we have discussed, all the root problems are due to only three reasons:
- No tools are used.
- No process is defined.
- Many resignations.
52) Which of the following is the key benefit of multi-vari charting?
- It keeps track of the time when measurements were made
- It graphically displays the variation in a process
- It assists in the breakdown of components of variation
- It is much easier to plot than most control charts
A multi-vari chart is a graphical representation of multiple variables on the same chart. Data variation can come from multiple sources.
53) What is lean philosophy?
- Helps to provide a perfect value through a perfect value creation process that has zero waste
- Continuous Improvement
- Higher output by encouraging people to work hard and have targets
- Reducing cost and improving purchasing power. When samples are drawn out of a population randomly, what is said to be true?
Lean philosophy: Lean six sigma is a philosophy for performance improvement by removing waste and reducing variation. This philosophy removes eight kinds of defects. This method relies on collaborative team effort.
54) When samples are drawn out of a population randomly, what is said to be true?
- The sample mean is always the same as the population mean
- The sample standard deviation will be the same as population standard deviation
- The sampling distribution approaches normality with an increase in sample size
- The sampling distribution would be triangular if the population is distributed as a triangular distribution
A random sampling is a sampling technique. Each sample has an equal opportunity of being chosen and the sample chosen is the unbiased representation of the entire population.
55) Which of the following tools is most commonly used in the define phase of a project?
- Affinity diagram
- Control chart
- Failure mode and effects analysis
- Data collection checklist
Define is the first phase of the DMAIC phase of six sigma project. A control chart is the most effective tool used in the define phase.
56) Which of these is considered a prioritization tool?
- Customer needs prioritization
- Focus Groups
- Nominal Group Technique
Multi-voting is a group decision making technique used for brain storming of ideas and prioritizing them. This technique reduces options to prevent information overload. Multi-voting is also known as N/3 voting. N refers to the total number of ideas.
57) Which is true about critical path?
1. Zero slack
2. Event oriented
3. Shortest path
4. Time and cost not considered
A critical path analysis uses network analysis and is widely used in project management. A critical path analyses helps to schedule and manage complex projects a critical path has zero slack.
58) The critical path of the project is best described as
Ans:(A) a series of steps with the highest costs(B) The tasks in the project which have the highest risk of failure(C) the sum of the tasks with the shortest time requirements (D) longest path from the start to the completion of the project
A critical path is a visual network planning tool. Critical path is the longest path from the time of beginning of the project till the end.
59) Which of the following statistical tests should be used by the Green Belt for testing the means between two inter-related groups?
- 2 Sample t assuming equal variances
- 2 Sample t assuming unequal variances
- Paired t-test
- z test
A paired test is used to determine if the mean difference between the two sets of observations is zero. In a paired sample t-test, there is a twice measurement of each subject or entity. This results in a pair of observation.
60) Standard Deviation in Six Sigma applications is referred to as the difference from the:
- Specification limits
- Nearest fit value
A standard deviation in six sigma applications that lets you know how the data points are grouped around the mean for a specific given process, which in turn tells you how much variation exists.
61) In a typical DFSS Approach, which of these stages figures in most DFSS approaches?
In the design for six sigma (DFSS) approach in six sigma, is an improvement process in the six sigma to develop new processes or products. The DFSS approach can also be applied if the current process requires an incremental improvement.
62) Which of these tools/techniques represent “continuous improvement”?
- Six Sigma
A kaizen or continuous improvement is a method of identifying opportunities and waste reduction. This practice is formalized by lean.
63) Japanese 5S methodology is created and used for:
- Continuous Improvement
- Prevent Defects
- Creating a productive work environment
- Reduce Variation
The Japanese 5s method supports lean in its basic form. The 5S stands for sort, straighten, shine, standardize, and sustain and is based on the Japanese concept for housekeeping (seiri, seiton, seiso, seiketsu, and shitsuke). This method helps organizations to maintain simplified and streamlined work environment.
64) What does OEE stand for?
- Overall Equipment Effectiveness
- Overall Estimation Effectiveness
- Overall Equipment Estimation
- Overall Effective Estimation
The overall equipment effectiveness is a measure of the manufacturing productivity. He manufacturing productivity is calculated by taking into the sub-components of manufacturing process like availability, performance and quality. OEE is the ratio of productive time to the planned production time.
OEE = (Good Count × Ideal Cycle Time)/ Planned production time
65) Which of the following techniques used in DOE helps you in identifying pure error?
A blocking technique helps to identify variables that are not important to the experimenter. Blocking technology reduces variability. Typically, blocking is an arrangement of experimental units in groups or blocks which are similar.
66) 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 graph plotting visuals plotting performance on x-axis and time on the y-axis. Control chart has three attributes; Upper control limit (UCL), Lower control limit (LCL) and average or center line of the data. The upper control limit is a three process control above the standard deviation.
67) One of the purposes of using a fishbone diagram is to:
- Separate a problem into smaller components
- Identify and classify sources of variations into major groups
- Define the problem in sequential order
- Show the relationship between parameters
A fish bone diagram is also called a cause-effect diagram. It is a visualization tool to display as many causes as possible for a problem. It sorts ideas into categories. This is a more structured method in cause and effect analysis.
68) Which approach talks about equipment effectiveness?
- Six Sigma
The total productive maintenance (TPM) is a new concept and a system of the machines, equipment, processes, and employees that add business value to an organization. This concept is used in equipment effectiveness.
69) The best metric for measuring defectives is:
The best metrics for measuring defectives in six sigma is parts per million defective (PPM). PPM is used to get the more accurate measure of defective rate. This method is more apt when the number of defective products produced is very small and percentage defective is not very effective.
70) If the Measure stage in a DMAIC approach is all about measuring the data for the existing process, what is the main objective in the Measure phase in a DFSS approach?
- Measure what you can measure
- Measure what the customer wants you to measure
- Set the key measurement steps and metrics
- Define operational metrics
The DFSS approach is used to design a product or service from scratch. This approach produces a very low defect level product or service. To produce such a product or service the customer expectations and needs should be measured.
71) All the factors that might contribute to a production problem must be discovered. Which among the following problem-solving tools might be the best choice?
- Pareto diagrams
- Fishbone diagrams
- Control charts
A fish bone diagram identifies all the possible cause and effect to identify the root cause of a problem.
72) Which of the following tools is used extensively in quality function deployment (QFD)?
Ans:(A) Affinity diagram
(B) Matrix diagram
(C) Cause and effect diagram
(D) Activity network diagram
Quality function deployment (QFD) is a research tool and a systematic method used to modify products to meet customer requirements. QFD is used to find the quality elements and engineering management measures that have the greatest influence on customer needs. Relationship matrix diagram gives complex relationships between quality elements and customer needs and is displayed with signs or weights.
73) Which of the following is the LEAST likely tool to assist the problem definition stage of Six Sigma?
- CTQ trees
- Pareto analysis
- Product yield data
- Control charts
The problem definition stage is the first stage in six sigma. DMAIC is a five-stage process of six sigma of problem-solving. “Define” is the first stage. Product yield data does not support the first stage in Six sigma.
74) In a typical Measure Phase, which of the following activities should a Green Belt perform first?
The measured phase has more numeric and data analysis. The MSA( measurement system analysis) will quantify the amount of variation in the data induced by the measuring system. Conducting MSA can be very exhaustive.
75) In a typical MSA GAGE RR study conducted, what should the Six Sigma team determine about the Measurement System first?
The GAGE RR study is conducted in the measured phase of the six sigma project. It measures the accuracy of the project.
76) Which of the following scenarios is best suited to use an X-bar and R chart?
- A smaller sample size is needed
- It is necessary to know when to investigate a process for causes of variation
- The machine capability is wider than the specification
- An acceptable quality level must be established
The X-Bar chart is used to plot the process mean and process range. The R-chart is used to review the process variation which must be in control to interpret correctly the X-Bar chart.
77) 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
78) “Forming, Storming, Norming, and Performing” are terms that describe
(A) Process variation reduction and improvement phases
(B) Root Cause identification and corrective action
(C) Stages of team growth
(D) Steps of the brainstorming process
Teams can perform better collectively than as individuals to achieve common goals. “Forming, Storming, Norming, and Performing” are terms that describe team growth and the various stages involved.
79) Which item should not be identified in the Define Phase?
- Root Causes
- The key problem area
- Possible financial loss
The define phase in DMAIC consists of identifying the business opportunity, key problem areas, selecting the key resources, and initiating the project charter. This phase is to define all the possible elements of a project.
80) The distribution that follows principles of an exponential distribution is:
A Poison distribution is a discrete probability distribution of the number of events in a fixed period of time, and the exponential distribution deals with the time between occurrences of successive events as time flows by continuously. A Poisson distribution can be derived from the exponential distribution.
81) For small incremental changes which Japanese technique is useful?
Kaizen technology in Six Sigma is useful for the systematic achievement of small incremental changes in processes to achieve efficiency and quality. Kaizen is also known as continuous improvement
82) Poka-yoke is best defined as:
- Capturing the voice of the customer
- Improving machine efficiency
- Reducing field failures to virtually zero
- Preventing controllable defects
Poka–Yoke is an approach for mistake-proofing to eliminate or prevent errors. This approach makes use of simple tools to prevent errors.
83) Which of the following is NOT necessary for the Six Sigma team to update in the Project Charter in the Define Phase?
- Project Name and Description
- Business need
- Project purpose
DMAIC – Define, measure, analyze, improve and control is a six sigma methodology. A project charter is the first step in define process. A project charter can create or destroy a successful project.
84) Which of the following distributions describes the ratios of two variances drawn from the same normal population?
- F statistic
- Student”s t-test
F-test is a statistical test that compares the variances of two samples taken from the populations with different variances to test the hypothesis. The objective of F-test is to check the differences in the sample variance.
85) 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 asfish bonediagram helps to visualize many potential caused for the specific problem.
86) Which of the following is an example of a Primary metric for Six Sigma projects?
- Morale of employees
- Average turnover/cycle time
- Customer Satisfaction
The primary metrics is also known as process metrics. Usually, they are process defects, process cycle time, and process consumption.
87) Which matrix diagram illustrates the relationship between three planes?
- Control charts
A matrix diagram depicts the relationship between two or more groups. A basic Y shaped diagram showed the relationship between three groups in a circular motion.
88) Which of the following measures of central tendency is preferred when the data does not have outliers?
- None of the above
Most populations exhibit normality, mean is the most suitable central tendency used to describe normal data.
89) Poka Yoke is a lean manufacturing concept that is used for what purpose?
- Process levelling
- Mistake proofing
- Process visualization
- Quick set up
Poka-Yoke is a Japanese word which means mistake proofing. This method is used in six sigma for eliminating errors.
90) For a process working at 5 Sigma level, how many opportunities are considered to lie outside of the specification limits provided by the customer?
Sigma 4 level indicates the maximum level of defects per million in a process or a system and relates to the overall percentage of accuracy. A 5 sigma level 233 errors per million
91) The most important factor for the success of six sigma projects is:
- Leadership support
- Team support
- Inter-department harmony
A six sigma process is aimed at reduction of variation, defects and risks. To implement six sigma leadership support is very important.
92) In a 4 sigma level process, how many opportunities lie outside the specification limits provided by the customer?
Sigma 4 level indicates the maximum level of defects per million in a process or a system and relates to the overall percentage of accuracy. A 4 sigma level 6210 errors per million.
93) Which analysis helps to prioritize customer requirements?
- Control charts
Kano analysis helps to prioritize customer requirements, once they are identified. Kano analysis is used in define phase of DMAIC process in six sigma.
94) Which of the following errors is typically associated with the notion, “False positive”?
- Type I error
- Type II error
- Type III error
- Depends on the experiments
A Type I error occurs when a null hypothesis is rejected even if it is true. The error accepts the alternative hypothesis, despite it being attributed to chance. Also referred to as a “false positive”.
95) Which of these are categorized under Precision in a GAGE RR Study?
- Repeatability and Reproducibility
A GAGE RR study or repeatability and Reproducibility is useful for evaluating the capability of a measurement system.
96) What is overproduction type of waste?
- Producing excess quantity than needed
- Producing lower quality and more quantity
- Producing lower quantity with higher quality
- Producing lower quantity than needed
Overproduction type of waste means producing more quantity than required.
97) When is FMEA process generally performed?
- Begins during the conceptualization stages of design and continues throughout the project.
- Just after the production tool is authorized
- Ends as soon as conceptualization is done
- Performed during the design stage
Failure mode and Effect analysis (FMEA) is a systematic method/approach o identify the possible failure in design, a manufacturing or assembly process, or a product or service. This process begins during the conceptualization of the project and continues throughout the project lifecycle.
98) In 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
Anything that does not contribute to the functionality of the final product is considered as a “Waste” in lean. Which means that the time spent on fixing defects is considered as waste.
99) What is COPQ?
- Cost of production quantity
- Cost of poor quality
- Cost of production quality
- Cost of Poor quantity
The cost of poor quality or poor quality costs occur when the product is not manufactured up to the mark. The COPQ would vanish if all they systems and products manufactured are perfect.