Lean Six Sigma Green Belt Practice Exam — All Questions

In the Define phase, what is the primary purpose of a project charter?

• a.To document the final control plan
• b.To perform hypothesis testing on the data
• c.To formally authorize the project and align the team on problem, scope, goal, and business case✓
• d.To calculate the process sigma level

The charter is the foundational Define deliverable: it states the problem, scope, goal, business case, team, and timeline so the project is authorized and everyone shares the same objective. Sigma calculations, control plans, and hypothesis tests come in later DMAIC phases.

A SIPOC diagram is used to define which of the following?

• a.The high-level process: Suppliers, Inputs, Process, Outputs, and Customers✓
• b.The financial return on the project
• c.The statistical distribution of a critical output
• d.The root cause of every defect

SIPOC gives a high-level map of Suppliers, Inputs, Process, Outputs, and Customers to bound the process under study. It is a scoping tool, not a statistical, financial, or root-cause analysis tool.

"Critical to Quality" (CTQ) characteristics are best described as:

• a.Measurable product or process features that translate the customer's needs into requirements✓
• b.The control limits on a process behavior chart
• c.Non-value-added steps in the value stream
• d.The team members assigned to the project

CTQs convert the Voice of the Customer into specific, measurable requirements the process must meet. They are derived from customer needs, not from team rosters, control charts, or waste categories.

Which tool helps a Green Belt prioritize which projects or problems to work on by weighting customer requirements against options?

• a.Ishikawa (fishbone) diagram
• b.Histogram
• c.Pugh matrix or prioritization matrix✓
• d.Control chart

A prioritization or Pugh matrix scores options against weighted criteria to guide selection. Fishbone diagrams find causes, control charts monitor stability, and histograms show distribution shape.

A process inspects 500 units, each having 8 opportunities for a defect, and finds 20 defects. What is the DPMO?

• a.2,500
• b.40,000
• c.250
• d.5,000✓

DPMO = defects / (units x opportunities) x 1,000,000 = 20 / (500 x 8) x 1,000,000 = 20 / 4,000 x 1,000,000 = 5,000. Each answer that ignores the opportunity count or the scaling factor is incorrect.

Defects Per Unit (DPU) is calculated as:

• a.Total number of defects divided by total number of units✓
• b.Total number of defects times 1,000,000
• c.Number of units divided by number of defects
• d.Defects divided by the number of opportunities only

DPU = total defects / total units, a simple ratio of how many defects occur per unit produced. Multiplying by a million or dividing by opportunities describes DPMO or DPO, not DPU.

Using the common long-term sigma table (with the 1.5-sigma shift), a process operating at approximately 66,807 DPMO corresponds to what sigma level?

• a.2 sigma
• b.4 sigma
• c.3 sigma✓
• d.6 sigma

On the standard shifted sigma table, roughly 66,807 DPMO equals about a 3-sigma process (about 93.3% yield). Six sigma is about 3.4 DPMO and four sigma is about 6,210 DPMO.

Which type of data is 'the number of scratches found on each painted panel'?

• a.A specification limit
• b.Nominal data with no order
• c.Continuous (variable) data
• d.Discrete (attribute/count) data✓

Counts of defects are discrete attribute data because they take whole-number values. Continuous data (like length or weight) can take any value on a scale, and a count is not a specification limit.

In a Measurement System Analysis (Gage R&R), 'reproducibility' refers to the variation caused by:

• a.The natural variation of the manufacturing process
• b.Different appraisers measuring the same part with the same gage✓
• c.The same appraiser measuring the same part repeatedly
• d.The width of the specification tolerance

Reproducibility is the appraiser-to-appraiser (between-operator) variation. The same appraiser repeating a measurement is repeatability, and neither describes process variation or the tolerance itself.

When testing whether a process change produced a statistically significant effect, a p-value of 0.02 against an alpha of 0.05 means:

• a.The effect size is guaranteed to be large
• b.Reject the null hypothesis; the result is statistically significant✓
• c.Fail to reject the null hypothesis; no significant effect
• d.The test is invalid and must be repeated

Because the p-value (0.02) is less than alpha (0.05), you reject the null hypothesis and conclude the effect is statistically significant. Statistical significance does not by itself measure the size or practical importance of the effect.

A Pareto chart supports the Analyze phase by helping the team:

• a.Focus on the 'vital few' categories that account for most of the problem✓
• b.Estimate the population standard deviation
• c.Prove causation between two variables
• d.Monitor a process over time for stability

The Pareto principle directs attention to the small number of categories that produce the majority of the defects or cost. It does not establish causation, track stability over time, or estimate spread.

A correlation coefficient (r) of 0.85 between two variables indicates:

• a.A strong negative linear relationship
• b.A strong positive linear relationship between the variables✓
• c.No relationship between the variables
• d.That one variable definitely causes the other

An r near +0.85 signals a strong positive linear association, meaning the variables tend to rise together. Correlation alone never proves causation, and a negative relationship would show a negative r.

The '5 Whys' technique is primarily used to:

• a.Drill down from a symptom to an underlying root cause✓
• b.Set the sample size for a study
• c.Build a control chart
• d.Calculate process capability indices

Asking 'why' repeatedly moves the team from the visible symptom toward the deeper root cause. It is a qualitative root-cause tool, not a method for capability, sampling, or control charting.

In hypothesis testing, a Type I error (alpha) occurs when you:

• a.Fail to reject a null hypothesis that is actually false
• b.Measure a part with the wrong gage
• c.Choose too large a sample size
• d.Reject a null hypothesis that is actually true (a false positive)✓

A Type I error is a false positive: concluding an effect exists when it does not, which happens with probability alpha. Failing to detect a real effect is a Type II (beta) error.

A designed experiment (DOE) that studies two factors, each at two levels, in every combination is called a:

• a.One-factor-at-a-time (OFAT) study
• b.Fractional factorial design
• c.Full factorial 2^2 design✓
• d.Simple linear regression

Testing every combination of 2 factors at 2 levels each is a full factorial 2^2 design (four runs). Changing one factor at a time is OFAT, and a fractional factorial deliberately runs only a subset of the combinations.

Poka-yoke, applied in the Improve phase, refers to:

• a.A statistical sampling plan
• b.A supplier scorecard
• c.Mistake-proofing that prevents or immediately detects errors✓
• d.A capacity-planning calculation

Poka-yoke is error- or mistake-proofing that makes a defect impossible or obvious, such as a connector that only fits one way. It is a prevention technique, not a sampling, capacity, or supplier-rating method.

A process has available production time of 480 minutes per shift and customer demand of 240 units per shift. What is the takt time?

• a.480 minutes per unit
• b.2 minutes per unit✓
• c.0.5 minutes per unit
• d.240 minutes per unit

Takt time = available time / customer demand = 480 / 240 = 2 minutes per unit, the pace needed to meet demand. Inverting the ratio or ignoring demand gives the wrong result.

The main purpose of a control chart in the Control phase is to:

• a.Rank problems from most to least frequent
• b.Map the suppliers and customers of a process
• c.Prove a factor is statistically significant
• d.Distinguish common-cause variation from special-cause variation over time✓

Control charts plot data over time with control limits so teams can tell routine common-cause variation from special-cause signals that need action. Ranking, mapping, and significance testing are done with other tools.

A process has USL = 110, LSL = 90, mean = 100, and standard deviation = 2.5. What is the Cp (process capability)?

• a.0.67
• b.1.00
• c.2.00
• d.1.33✓

Cp = (USL - LSL) / (6 x sigma) = (110 - 90) / (6 x 2.5) = 20 / 15 = 1.33. A Cp of 1.33 corresponds to a four-sigma capable process when centered.

In Lean, which of the following is one of the classic categories of waste (muda)?

• a.Value-added processing
• b.Overproduction✓
• c.Standardized work
• d.Continuous flow

Overproduction, making more or sooner than needed, is one of the classic wastes and is often called the worst because it hides others. Standardized work, value-added processing, and continuous flow are goals, not wastes.

The 5S methodology (Sort, Set in order, Shine, Standardize, Sustain) is primarily aimed at:

• a.Calculating rolled throughput yield
• b.Organizing and maintaining an efficient, orderly workplace✓
• c.Performing a measurement system analysis
• d.Designing a full factorial experiment

5S creates and sustains a clean, organized, visual workplace that exposes abnormalities and supports flow. It is a workplace-organization method, not an experimental, yield, or measurement technique.

A control plan created at the end of a project is intended mainly to:

• a.Sustain the gains by specifying what to monitor, how, and the reaction plan if limits are exceeded✓
• b.Replace the need for any ongoing measurement
• c.Define the original problem statement
• d.Calculate the project's net present value

The control plan documents the key characteristics to monitor, the method and frequency, and the response if the process drifts, so improvements hold over time. It defines ongoing monitoring rather than eliminating it, and it is not a Define or finance tool.

Which of the following is the best-written problem statement for a Define-phase charter?

• a.Over the last 6 months, 14% of orders shipped after their promised date, versus a 2% target, costing about $80K in expedite fees✓
• b.Because the warehouse crew keeps mishandling orders, the team should buy new routing software this quarter to stop the delivery complaints
• c.The team should install a new scheduling system to fix late shipments
• d.Late shipments are caused by the packaging department and must be corrected

A sound problem statement is specific, measurable, and neutral: it states what is wrong, where, when, and the magnitude (baseline vs target), without naming a cause or a solution. Options that pre-assign a cause ('packaging department') or a solution ('install a system') violate that rule.

A goal statement in a project charter should be:

• a.A list of every stakeholder affected by the project
• b.Broad and open-ended so the team is not constrained
• c.Focused on the suspected root cause of the defect
• d.SMART — Specific, Measurable, Achievable, Relevant, and Time-bound✓

Goal statements follow the SMART criteria so success is unambiguous and time-bound (e.g., 'reduce late shipments from 14% to 2% by Q4'). Vague or open-ended goals cannot be verified, and root-cause identification belongs to Analyze.

The business case section of a project charter primarily answers which question?

• a.Which appraiser measured the parts
• b.What the control limits of the process are
• c.Why the organization should invest resources in this project now✓
• d.Which statistical test should be run on the data

The business case links the project to strategy and finances, explaining the value and urgency of doing the work now. It justifies the investment; statistical tests, control limits, and appraisers are downstream execution details.

Defining what is 'in scope' and 'out of scope' on a charter is important mainly because it:

• a.Replaces the need for a control plan
• b.Sets clear process boundaries and helps prevent scope creep✓
• c.Guarantees the project will finish under budget
• d.Calculates the process sigma level

Scope boundaries bound the process being improved and protect the team from scope creep — the uncontrolled expansion of work. They do not compute capability or guarantee budget outcomes.

'Voice of the Customer' (VOC) refers to:

• a.The collected needs, expectations, and preferences of customers, in their own terms✓
• b.The internal cost targets set by the finance department
• c.The upper and lower control limits of a process
• d.The regulatory limits imposed by a government agency

VOC captures what customers need and expect, expressed in their language, and is later translated into measurable CTQ requirements. Internal cost targets are the Voice of the Business, and control/regulatory limits are separate concepts.

Which of these is a REACTIVE source of Voice of the Customer data?

• a.Warranty claims and customer complaints✓
• b.A designed customer interview
• c.A market-research survey sent before launch
• d.A proactively scheduled focus group

Reactive VOC arrives without you asking — complaints, returns, and warranty claims come to you after a problem. Surveys, interviews, and focus groups are proactive methods you initiate to gather customer input.

Interviews, surveys, and focus groups are examples of what kind of VOC gathering?

• a.Measurement system analyses
• b.Statistical process control tools
• c.Reactive methods that wait for feedback to arrive
• d.Proactive methods the team deliberately initiates✓

Proactive VOC methods actively solicit input from customers before problems escalate. Reactive methods (complaints, returns) wait for feedback; SPC and MSA are Measure/Control analytical tools.

In the Kano model, a 'must-be' (basic) requirement is one that:

• a.Causes dissatisfaction when absent but is simply expected when present✓
• b.Increases satisfaction linearly as performance improves
• c.Delights customers when present because they never expected it
• d.Has no effect on customer satisfaction either way

Kano basic (must-be) needs are taken for granted: their absence angers customers, but their presence earns no extra credit. Delighters exceed expectations, and performance (one-dimensional) needs scale satisfaction with performance.

A Kano 'delighter' (exciter/attractive) feature is characterized by the fact that:

• a.Its absence makes customers very angry
• b.Customers explicitly ask for it in every survey
• c.Satisfaction rises in direct proportion to how much is delivered
• d.Its presence delights customers, but its absence does not dissatisfy them✓

Delighters are unexpected features that surprise and please; because customers do not expect them, their absence causes no dissatisfaction. Must-be needs anger customers when missing, and performance needs scale linearly.

A Kano 'performance' (one-dimensional) requirement is one where:

• a.More is better — satisfaction increases roughly linearly with the level delivered✓
• b.The requirement is impossible to measure
• c.Presence or absence has no effect on satisfaction
• d.The feature only ever dissatisfies, never satisfies

Performance (one-dimensional) needs — like fuel economy or battery life — track satisfaction linearly: the more you deliver, the happier the customer. They contrast with basic (must-be) and delighter needs.

The primary purpose of a CTQ tree (critical-to-quality tree) is to:

• a.Break a broad customer need down into specific, measurable requirements✓
• b.Estimate the standard deviation of the process
• c.Plot data points over time to detect special causes
• d.Rank defects from most to least frequent

A CTQ tree drills a general need (e.g., 'fast service') into drivers and then into measurable CTQs (e.g., 'answer within 30 seconds'). Pareto charts rank defects, and control charts monitor time-ordered data.

A customer says, 'I want my coffee hot.' Which of the following best translates this VOC into a CTQ?

• a.Coffee quality is important to the business
• b.The barista should try harder to keep coffee warm
• c.Serving temperature must be between 155 and 175 degrees Fahrenheit✓
• d.Customers value hot coffee

A CTQ converts a subjective need into a specific, measurable requirement with a target and limits (temperature 155-175 F). Restating the need or an intention ('try harder') is not measurable and cannot be verified.

In a SIPOC, what does the 'I' stand for, and what does it represent?

• a.Issues — the known problems to be solved
• b.Inspection — the quality checks within the process
• c.Indicators — the key performance metrics
• d.Inputs — the materials, information, and resources entering the process✓

SIPOC = Suppliers, Inputs, Process, Outputs, Customers. Inputs are what suppliers provide into the process (materials, data, resources). It is a scoping tool, not an inspection or metrics list.

In a SIPOC diagram, the 'Outputs' column captures:

• a.The people who supply raw materials
• b.The root causes of process defects
• c.The equipment used inside the process
• d.The products, services, or information the process delivers to customers✓

Outputs are what the process produces and hands to the customers (goods, services, information). Suppliers provide inputs, and root causes are found later in Analyze.

When building a SIPOC, the team typically defines the process as a high-level flow of how many major steps?

• a.Every micro-step, often 50 or more
• b.About 4 to 7 high-level steps with a clear start and stop point✓
• c.Only the final inspection step
• d.Exactly two steps in all cases

SIPOC keeps the process at a high level — roughly 4-7 major steps with defined start and stop boundaries — to scope the effort. Detailed process mapping with many micro-steps comes later in Measure.

Stakeholder analysis in the Define phase is used to:

• a.Determine the sample size for data collection
• b.Calculate the DPMO and the corresponding long-term sigma level of the current process baseline
• c.Identify who is affected by or can influence the project, and plan how to engage them✓
• d.Set the upper and lower specification limits

Stakeholder analysis maps the people affected by or influential over the project and how to gain their support or manage resistance. It is a change-management tool, not a statistical or specification-setting one.

In a RACI matrix, the 'R' identifies the person who is:

• a.Reviewing — the one who audits the results
• b.Responsible — the one who actually does the work✓
• c.Removed — the one with no involvement
• d.Reporting — the one who publishes status

In RACI (Responsible, Accountable, Consulted, Informed), the Responsible party performs the task. Accountable owns the outcome, Consulted gives input, and Informed is kept up to date.

A best practice for the 'Accountable' role in a RACI chart is that:

• a.Accountability rotates daily among team members
• b.Every task should have at least three accountable people
• c.Exactly one person is accountable for each task or deliverable✓
• d.The accountable person must also do all the hands-on work

RACI assigns a single Accountable owner per task so ownership is unambiguous ('the one throat to choke'). Multiple accountable parties dilute ownership; the Responsible person does the hands-on work.