ASQ Certified Six Sigma Green Belt (CSSGB) Exam — Questions and Answers

Question 1: What is the primary purpose of a reaction plan in the Control phase?

To assign blame for process failures
To celebrate project completion milestones
To document lessons learned from the Define phase
To define corrective actions when a process goes out of control (Correct answer)

Correct answer: To define corrective actions when a process goes out of control

A reaction plan specifies the immediate steps to take when monitoring detects an out-of-control condition.

Question 2: A process has a Cpk of 0.85. What does this indicate?

The process is centered and fully capable of meeting specification limits
The process is not capable of consistently producing output within specification limits (Correct answer)
The process has negligible variation and exceeds all customer requirements
The process is capable but slightly off-center within the specification limits

Correct answer: The process is not capable of consistently producing output within specification limits

A Cpk below 1.00 means the process is not capable — it will produce defects outside specification limits. A Cpk of at least 1.33 is typically required to demonstrate adequate short-term capability, and 1.67 or higher for critical characteristics.

Question 3: When collecting Voice of Customer data, which method captures customers' exact words and unfiltered opinions BEST?

Historical complaint logs
Internal process audits
Direct customer interviews (Correct answer)
Employee surveys

Correct answer: Direct customer interviews

Direct customer interviews allow teams to hear unfiltered VOC in the customer's own words, reducing interpretation bias.

Question 4: Which of the following Lean tools is primarily used to visualize the flow of materials and information, distinguish between value-added and non-value-added activities, and identify opportunities for improvement across an entire process?

Control Chart
Pareto Chart
Fishbone Diagram
Value Stream Map (VSM) (Correct answer)

Correct answer: Value Stream Map (VSM)

A Value Stream Map (VSM) is a flowcharting tool used to illustrate, analyze, and improve all the steps in a product or service's value stream. A key function of VSM is to identify and eliminate non-value-added activities (waste), thereby reducing lead time.

Question 5: A control chart with very tight control limits relative to specifications suggests:

The process requires immediate improvement action
The control limits were incorrectly calculated from specification data
The process is highly capable and the measurement system may be too sensitive (Correct answer)
The process is barely capable of meeting specifications

Correct answer: The process is highly capable and the measurement system may be too sensitive

When control limits are much tighter than specification limits, the process Cpk is high, indicating excellent capability with ample room between natural variation and customer tolerances.

Question 6: A call center manager wants to determine if there is a statistically significant difference in the average call handling time between a team that received new training and a team that did not. Both teams have fewer than 30 members. What is the most appropriate statistical test to use?

1-Sample t-Test
ANOVA
Chi-Square Test
2-Sample t-Test (Correct answer)

Correct answer: 2-Sample t-Test

A 2-Sample t-Test is used to compare the means of two independent groups to determine if they are statistically different from each other. Since the manager is comparing the average call times (continuous data) of two different teams (two groups), the 2-Sample t-Test is the correct tool.

Question 7: What is a 'fractional factorial' design used for in DOE?

To eliminate all interaction effects from analysis
To study a subset of all possible factor combinations and reduce runs (Correct answer)
To increase the number of experimental runs for better accuracy
To ensure full replication of every experimental condition

Correct answer: To study a subset of all possible factor combinations and reduce runs

Fractional factorial designs study a carefully chosen fraction of all factor combinations, reducing runs while still estimating main effects.

Question 8: Which sampling method ensures every possible sample of a given size has an equal probability of being selected?

Convenience sampling
Systematic sampling
Simple random sampling (Correct answer)
Stratified sampling

Correct answer: Simple random sampling

Simple random sampling gives every possible combination of the desired sample size an equal chance of selection, providing an unbiased representation of the population.

Question 9: In Failure Mode and Effects Analysis (FMEA), the Risk Priority Number (RPN) is calculated by multiplying:

Severity, Likelihood, and Exposure
Severity, Occurrence, and Detection (Correct answer)
Frequency, Criticality, and Controllability
Probability, Impact, and Urgency

Correct answer: Severity, Occurrence, and Detection

RPN = Severity × Occurrence × Detection. Each factor is rated on a 1–10 scale. Severity measures impact if the failure occurs, Occurrence measures how frequently it might happen, and Detection measures how likely the current controls are to catch the failure before it reaches the customer. Higher RPN scores prioritize remediation efforts.

Question 10: During Define, what is the MAIN purpose of conducting a stakeholder analysis?

To determine which customers to survey for VOC data
To sequence the DMAIC phase milestones
To identify individuals who can influence the project's success and plan engagement strategies (Correct answer)
To calculate the financial ROI of the project

Correct answer: To identify individuals who can influence the project's success and plan engagement strategies

Stakeholder analysis identifies people with power or interest in the project so the team can proactively manage their support or resistance.

Question 11: Which of the following best describes the Lean principle of 'Seek Perfection'?

Continuously striving for incremental improvement with no end state (Correct answer)
Achieving zero defects on the first production run
Eliminating all seven wastes permanently
Implementing standardized work across all processes

Correct answer: Continuously striving for incremental improvement with no end state

Seeking perfection in Lean is an ongoing, never-ending pursuit of continuous improvement (kaizen) rather than a single achievable goal.

Question 12: A team applies the SIPOC in the Analyze phase to trace a defect. Which element of SIPOC is most useful for identifying the source of a faulty input?

Output
Process step
Customer
Supplier (Correct answer)

Correct answer: Supplier

The Supplier element identifies who or what provides each input, making it the starting point for tracing faulty inputs to their origin.

Question 13: What does the term 'takt time' represent in Lean manufacturing?

The time a product spends waiting in a queue
The rate of customer demand expressed as available time divided by demand (Correct answer)
The time it takes to complete one unit from start to finish
The total processing time across all value-added steps

Correct answer: The rate of customer demand expressed as available time divided by demand

Takt time = available production time ÷ customer demand rate, setting the pace production must match to meet demand without overproduction.

Question 14: A spaghetti diagram is most useful in the Measure phase for:

Identifying statistical outliers
Plotting defect rates over time
Comparing the distribution of two groups
Visualizing physical movement of people or materials in a process (Correct answer)

Correct answer: Visualizing physical movement of people or materials in a process

A spaghetti diagram traces the actual physical path of people, materials, or information through a workspace, revealing waste in motion and transportation.

Question 15: Which DMAIC phase focuses on identifying the root cause of a process problem?

Analyze (Correct answer)
Measure
Define
Improve

Correct answer: Analyze

The Analyze phase uses data and statistical tools to identify and verify root causes of process problems.

Question 16: Which of the following Lean principles must be established before a pull system can function effectively?

Map the value stream
Define value
Seek perfection
Create flow (Correct answer)

Correct answer: Create flow

Flow must be established before pull can work — without continuous, uninterrupted flow, downstream signals cannot reliably pace upstream production.

Question 17: A Lean Six Sigma team finds that 20% of the product types account for 78% of customer complaints. Which tool was used to identify this insight?

Control chart
Scatter diagram
Pareto chart (Correct answer)
Box plot

Correct answer: Pareto chart

A Pareto chart ranks categories by frequency or impact, making it easy to identify the 'vital few' causes following the 80/20 principle.

Question 18: What kind of waste could the ensuing circumstance generate? More clothes is being produced than what the customer has ordered by a clothing manufacturer.

Transportation
Waiting
Over Production (Correct answer)
Over Processing

Correct answer: Over Production

Producing more goods than what is immediately required or ordered by the customer is a classic example of 'Over Production' waste in Lean Six Sigma. This type of waste leads to excess inventory, consumes unnecessary resources, and can hide other inefficiencies within the manufacturing process. It often results in increased storage costs, potential obsolescence, and inefficient use of labor and materials.

Question 19: Which of the following best describes a well-written problem statement in a Six Sigma project charter?

It quantifies the problem with baseline data, describes its impact, and avoids assigning blame or solutions (Correct answer)
It lists all stakeholders affected and their individual concerns about the process
It identifies the suspected root cause and proposes a corrective action
It outlines the expected financial savings once the project is complete

Correct answer: It quantifies the problem with baseline data, describes its impact, and avoids assigning blame or solutions

A strong problem statement is fact-based and measurable (e.g., 'defect rate is currently 12%'), describes business impact, and deliberately excludes root causes or solutions so the team investigates with an open mind.

Question 20: What statistical tool is used to test whether two or more population variances are equal?

Chi-square test
ANOVA
Levene's test (Correct answer)
t-test

Correct answer: Levene's test

Levene's test (and Bartlett's test) are used to assess the equality of variances across groups, an assumption required for many other statistical tests.

Question 21: When conducting a Kano analysis, which feature type has a symmetrical relationship — meaning more of it leads to more satisfaction, and less leads to more dissatisfaction?

Basic (must-be) needs
Performance (one-dimensional) needs (Correct answer)
Excitement (delighter) needs
Indifferent needs

Correct answer: Performance (one-dimensional) needs

Performance needs are linear: the more the feature is present, the more satisfied customers are, and vice versa.

Question 22: A manufacturer implements one-piece flow instead of batch processing. Which primary Lean benefit does this most directly achieve?

Shorter lead times and faster detection of quality defects (Correct answer)
Reduced labor costs through headcount reduction
Higher machine utilization rates
Simplified inventory accounting

Correct answer: Shorter lead times and faster detection of quality defects

One-piece flow reduces work-in-process inventory and exposes defects immediately at the next step rather than discovering them after a large batch has been completed.

Question 23: In Lean thinking, which activity would be classified as 'necessary but non-value-added'?

Regulatory compliance inspections (Correct answer)
Moving materials between buildings
Reworking defective parts
Storing finished goods in a warehouse

Correct answer: Regulatory compliance inspections

Regulatory inspections do not add value from the customer's perspective but are legally required and cannot be eliminated.

Question 24: What is the primary function of a control plan in the Control phase of DMAIC?

To document the procedures and monitoring needed to sustain process gains (Correct answer)
To perform a cost-benefit analysis of the project
To train team members on statistical tools
To identify new improvement projects

Correct answer: To document the procedures and monitoring needed to sustain process gains

A control plan documents the monitoring methods, response plans, and responsibilities needed to maintain the improvements achieved during the project.

Question 25: A Lean team maps a process and finds that 70% of cycle time is spent on activities the customer would not pay for. What category does this majority fall under?

Kaizen opportunities
Non-value-added but necessary activities
Value-added activities
Pure waste (muda) (Correct answer)

Correct answer: Pure waste (muda)

Activities that consume time and resources but do not transform the product in a way the customer values are pure waste and are primary targets for elimination.

Question 26: Which of the eight wastes was added to the original seven wastes identified by Taiichi Ohno?

Inventory
Non-utilized talent (Correct answer)
Waiting
Transportation

Correct answer: Non-utilized talent

The eighth waste, non-utilized talent or underutilized employee skills, was added later to complement Ohno's original seven wastes.

Question 27: A Green Belt is leading a short, focused, rapid improvement event with a cross-functional team to rearrange a workspace for better flow and efficiency. The event is expected to last 3-5 days and result in immediate changes. What is this type of event called?

A Gage R&R study
A project Tollgate review
A Kaizen event (Correct answer)
A stakeholder analysis

Correct answer: A Kaizen event

A Kaizen event (also called a Kaizen blitz or rapid improvement event) is a highly focused, short-term (typically 3-5 days) activity involving a cross-functional team to make significant improvements in a specific area.

Question 28: When performing a two-sample t-test, what assumption must be verified about the data distributions?

Data must follow a binomial distribution
Sample sizes must be equal
Data should be approximately normally distributed (Correct answer)
Data must be categorical

Correct answer: Data should be approximately normally distributed

The two-sample t-test assumes that the data from both populations are approximately normally distributed, especially important with small sample sizes.

Question 29: When a team performs regression analysis and finds that adding a second X variable increases R² from 0.72 to 0.73, the BEST interpretation is:

The model is now significantly better and ready for the Improve phase
R² should always be maximized regardless of the number of variables
The second variable adds minimal explanatory value and may not justify model complexity (Correct answer)
The second variable is highly significant and must be included

Correct answer: The second variable adds minimal explanatory value and may not justify model complexity

A marginal R² increase suggests the second variable contributes little additional explanatory power while adding model complexity, so its inclusion should be questioned.

Question 30: There is intrinsic volatility in a process that you are tracking over time. What method should you employ to control the process?

Increase the specification limits to ensure the process is capable
Take immediate action to identify root causes of the common cause variation
Continually and gradually improve the stable process (Correct answer)
Stop the process, identify the causes, and eliminate them

Correct answer: Continually and gradually improve the stable process

If a process is stable and under control (meaning only common cause variation is present), but its intrinsic volatility is still too high relative to customer specifications, the appropriate action is to continually and gradually improve the stable process. This involves making fundamental changes to the process system itself to reduce the inherent common cause variation, rather than reacting to individual data points or increasing specification limits.

Question 31: A Gage R&R study reveals that measurement system variation accounts for 35% of total observed variation. This result indicates:

Repeatability is worse than reproducibility
The measurement system needs improvement before data can be trusted (Correct answer)
The process has high variation compared to spec limits
The measurement system is acceptable for process control

Correct answer: The measurement system needs improvement before data can be trusted

AIAG guidelines classify a measurement system contributing >30% of total variation as unacceptable and requiring corrective action before use.

Question 32: What is the primary purpose of a hypothesis test during the Analyze phase?

To collect baseline data for the project
To determine if observed differences are statistically significant (Correct answer)
To implement process improvements
To create a project charter

Correct answer: To determine if observed differences are statistically significant

Hypothesis testing determines whether observed differences or relationships in data are statistically significant or due to random chance.

Question 33: During Improve phase solution selection, a solution scoring matrix (weighted criteria matrix) is used to:

Document the project charter requirements
Monitor the implemented solution over time
Objectively compare and rank potential solutions against weighted criteria (Correct answer)
Identify root causes of the problem

Correct answer: Objectively compare and rank potential solutions against weighted criteria

A weighted criteria (Pugh) matrix scores each solution alternative against important criteria weighted by importance to enable objective selection.

Question 34: A process improvement team wants to test whether the proportion of defective units differs between two production lines. Which test is most appropriate?

Mann-Whitney U test
Two-sample t-test
One-way ANOVA
Two-proportion z-test (Correct answer)

Correct answer: Two-proportion z-test

The two-proportion z-test compares proportions (attribute data) from two independent groups to determine if they are statistically different.

Question 35: A project team is implementing a solution to prevent assemblers from installing a computer component backward. They design a new version of the component with an offset pin that only allows it to be inserted in the correct orientation. Which Lean technique does this solution exemplify?

Kanban
Poka-Yoke (Correct answer)
SMED
5S

Correct answer: Poka-Yoke

Poka-Yoke is a Japanese term that means 'mistake-proofing' or 'error-proofing'. The redesigned component, which physically prevents incorrect assembly, is a classic example of this technique.

Question 36: A software development team keeps a backlog of hundreds of features coded but not yet released to users. Which waste does this represent?

Defects
Waiting
Over-processing
Inventory (Correct answer)

Correct answer: Inventory

Unreleased software features are analogous to inventory waste — work-in-process that is not yet delivering value to the customer.

Question 37: What is the primary purpose of a Failure Mode and Effects Analysis (FMEA) during the Analyze phase?

To build a control plan for sustaining improvements
To map the current state value stream
To calculate process capability
To prioritize potential failure modes by their Risk Priority Number (RPN) (Correct answer)

Correct answer: To prioritize potential failure modes by their Risk Priority Number (RPN)

FMEA identifies potential failure modes and scores them by RPN (Severity × Occurrence × Detection) to prioritize which risks to address.

Question 38: Which stakeholder group is considered the MOST important source for defining CTQs?

Process owners
External customers (Correct answer)
Project sponsors
Finance department

Correct answer: External customers

External customers are the primary source for CTQs because Six Sigma is fundamentally about delivering value that meets or exceeds customer needs.

Question 39: Which of the following best describes a tollgate review at the end of the Define phase?

An informal brainstorming session to generate improvement ideas
A statistical validation of the measurement system
A formal checkpoint where leadership reviews deliverables before the team proceeds to Measure (Correct answer)
A final presentation of project results to stakeholders

Correct answer: A formal checkpoint where leadership reviews deliverables before the team proceeds to Measure

A tollgate review ensures all required Define phase deliverables are complete and approved before advancing to the next phase.

Question 40: If a process has a long-term sigma level of 3.0, what is the approximate DPMO?

233
66,807 (Correct answer)
6,210
3,400

Correct answer: 66,807

A 3-sigma process (long-term, with 1.5σ shift) corresponds to approximately 66,807 DPMO.

Question 41: What is the key distinction between common cause variation and special cause variation?

Common cause always requires process redesign to eliminate
Special cause can only be detected with attribute data
Common cause is larger in magnitude than special cause
Common cause is inherent to the process; special cause is from an external, assignable factor (Correct answer)

Correct answer: Common cause is inherent to the process; special cause is from an external, assignable factor

Common cause variation is the natural, random variation built into a stable process, while special cause variation is due to identifiable, non-routine factors.

Question 42: In a control plan, 'frequency' refers to:

The sampling rate used to build the control chart baseline
How often the process is allowed to go out of control
The number of defects per million opportunities
How often a measurement is taken for a given CTQ or control variable (Correct answer)

Correct answer: How often a measurement is taken for a given CTQ or control variable

Frequency in a control plan specifies how often each characteristic must be measured (e.g., every hour, every 50 units) to detect shifts in the process in a timely manner.

Question 43: After implementing a process change, a team runs a two-sample t-test and obtains a p-value of 0.03. At α = 0.05, what should they conclude?

Fail to reject the null hypothesis; no significant difference
The sample size was too small to draw conclusions
Reject the null hypothesis; there is a statistically significant difference (Correct answer)
The process change had no practical significance

Correct answer: Reject the null hypothesis; there is a statistically significant difference

Since p-value (0.03) < α (0.05), the team rejects the null hypothesis, concluding there is a statistically significant difference between before and after.

Question 44: What is the relationship between process capability index Cp and specification width?

Cp = (6 × standard deviation) / (USL - LSL)
Cp = (USL - LSL) / (6 × standard deviation) (Correct answer)
Cp = (USL - LSL) / (3 × standard deviation)
Cp = Mean / (USL - LSL)

Correct answer: Cp = (USL - LSL) / (6 × standard deviation)

Cp compares the specification width (USL minus LSL) to the process spread (six standard deviations), measuring potential capability.

Question 45: What three characteristics of Six Sigma best capture why Senior Management finds it to be an effective approach for decreasing variance and enhancing processes?

Data Driven, Methodical, ROI Oriented
Data Driven, Creative, Streamlined
Customer Focused, Statistical Emphasis, Conformity - Driven
Customer Focused, Data Driven, ROI Oriented (Correct answer)

Correct answer: Customer Focused, Data Driven, ROI Oriented

Senior Management finds Six Sigma effective due to its core characteristics: it is Customer Focused, meaning all improvements are driven by what matters to the customer; it is Data Driven, relying on statistical analysis and facts to make decisions and measure progress; and it is ROI Oriented, ensuring that improvement projects deliver tangible financial benefits and a clear return on investment. These three aspects align Six Sigma with strategic business objectives.

Question 46: Which component of the Project Charter explicitly defines what is included and excluded from a Lean Six Sigma project?

Goal statement
Project scope (Correct answer)
Business case
Problem statement

Correct answer: Project scope

The project scope sets the boundaries of the project — what processes, products, locations, or time periods are in and out of scope. Without a clearly defined scope, teams risk scope creep and loss of focus.

Question 47: Which term describes the smallest detectable difference that a measurement instrument can reliably distinguish?

Calibration
Resolution (discrimination) (Correct answer)
Stability
Linearity

Correct answer: Resolution (discrimination)

Resolution (or discrimination) is the smallest increment a gauge can detect; it should be at least 1/10 of the total process variation.

Question 48: A Kaizen event conducted during the Improve phase is best characterized as:

A focused, short-duration team effort (typically three to five days) to rapidly implement targeted process improvements (Correct answer)
A multi-month statistical study to identify optimal process parameters
A structured root-cause analysis session led by the process owner
A tollgate review where the project sponsor approves the solution before piloting

Correct answer: A focused, short-duration team effort (typically three to five days) to rapidly implement targeted process improvements

Kaizen events (also called Kaizen blitzes or rapid improvement workshops) concentrate a cross-functional team on a specific process area for a brief, intensive period to design and implement improvements immediately, compressing months of change into days.

Question 49: A team performs a two-sample t-test comparing mean output before and after a process change and obtains p = 0.12 with α = 0.05. What action is recommended?

Fail to reject the null hypothesis; the difference is not statistically significant (Correct answer)
Permanently implement the process change
Declare the change effective and proceed to Improve
Reject the null hypothesis since p < 0.20

Correct answer: Fail to reject the null hypothesis; the difference is not statistically significant

Since p = 0.12 > α = 0.05, there is insufficient evidence to conclude the means differ; the null hypothesis of no difference is not rejected.

Question 50: What is the Z-score for a data point that is 2 standard deviations below the mean?

0.02
-2 (Correct answer)
+2
-0.2

Correct answer: -2

Z = (X - μ) / σ; a value 2 standard deviations below the mean yields Z = -2.

Question 51: Which of these 5S's is predominantly driven by management, despite the fact that management of a company must set the framework for all improvement efforts?

Sustain (Correct answer)
Shine
Sort
Straighten

Correct answer: Sustain

While all 5S principles require management support, 'Sustain' (Shitsuke) is predominantly driven by management. It involves maintaining the gains achieved through the other 4S's by embedding them into the company culture, providing ongoing training, and ensuring continuous auditing and reinforcement. This long-term commitment and cultural integration primarily fall under management's responsibility to ensure the 5S methodology endures.

Question 52: A sustained improvement in a transactional process is BEST evidenced by:

A one-time measurement showing the new process meets the target
A statistically significant shift in the process output metric sustained over 3-6 months post-implementation (Correct answer)
The team's subjective assessment that the process feels smoother
Management approval of the new standard operating procedure

Correct answer: A statistically significant shift in the process output metric sustained over 3-6 months post-implementation

True sustainment requires demonstrating that the improved performance has been maintained over a meaningful time horizon with statistical evidence, not just at a single point in time.

Question 53: Which type of data collection error occurs when inspectors change their rating criteria over time?

Appraiser bias
Instrument drift
Criteria drift (Correct answer)
Sampling bias

Correct answer: Criteria drift

Criteria drift happens when the standards or interpretation used for measurement gradually shift during a study.

Question 54: A Lean Six Sigma team uses a 2^3 full factorial experiment with center points. What is the primary reason for adding center points?

To balance the design across blocking variables
To increase the number of replicates for main effects
To reduce the number of experimental runs required
To detect curvature in the response and estimate pure error (Correct answer)

Correct answer: To detect curvature in the response and estimate pure error

Center points are added to a factorial design to test for curvature (non-linearity) in the response surface and provide an estimate of pure experimental error.

Question 55: A project has a stated baseline defect rate of 8% and a goal of reducing it to 3% within six months. Which charter element does this information belong to?

Goal statement (Correct answer)
Team roles section
Business case
Risk assessment

Correct answer: Goal statement

The goal statement captures the current baseline performance, the target improvement, and the timeline for achievement.

Question 56: What is the primary purpose of the Control Phase in a DMAIC project?

To brainstorm and implement a wide range of potential solutions.
To lock in the gains and ensure the improved process is sustained. (Correct answer)
To validate the measurement system's accuracy and reliability.
To identify the root causes of process variation using statistical tools.

Correct answer: To lock in the gains and ensure the improved process is sustained.

The primary purpose of the Control Phase is to ensure that the improvements made in the 'Improve' phase are maintained over the long term. This involves creating monitoring systems, standardizing the new process, and transferring ownership.

Question 57: A project team implemented a new stocking procedure to reduce order fulfillment time. To monitor the new process and ensure it remains stable, they track the average fulfillment time daily. Which tool is most appropriate for this task?

Statistical Process Control (SPC) Chart (Correct answer)
Pareto Chart
Failure Mode and Effects Analysis (FMEA)
Fishbone Diagram

Correct answer: Statistical Process Control (SPC) Chart

Statistical Process Control (SPC) charts are specifically designed to monitor process performance over time, distinguish between common cause and special cause variation, and detect when a process is becoming unstable.

Question 58: What is the primary purpose of a tollgate review at the end of the Define phase?

To verify that implemented solutions have achieved the target improvement
To confirm that the team has clearly defined the problem, scope, and goals and is ready to proceed to Measure (Correct answer)
To statistically validate the measurement system before collecting baseline data
To ensure that process control plans are in place to sustain gains

Correct answer: To confirm that the team has clearly defined the problem, scope, and goals and is ready to proceed to Measure

A Define tollgate is a structured checkpoint where the project sponsor and leadership confirm that the charter, problem statement, scope, goals, and team are sound before the team invests effort in data collection during the Measure phase.

Question 59: Which Define phase activity ensures the team and sponsor have aligned on what is IN scope and what is OUT of scope before proceeding?

Design of Experiments
Measurement system analysis
Scope definition in the project charter (Correct answer)
Statistical hypothesis testing

Correct answer: Scope definition in the project charter

Explicitly defining in-scope and out-of-scope boundaries in the project charter prevents scope creep and sets shared expectations.

Question 60: In hypothesis testing, a Type II error occurs when:

A true null hypothesis is rejected
The sample size is too large
A false null hypothesis is not rejected (Correct answer)
The significance level is set too low

Correct answer: A false null hypothesis is not rejected

A Type II error (beta error) is failing to reject a null hypothesis that is actually false — missing a real effect.

Question 61: What is the key difference between the Cp and Cpk process capability indices?

Cp is used for attribute data while Cpk is used for continuous variable data
Cpk accounts for process centering while Cp measures only spread relative to specification width (Correct answer)
Cp accounts for process centering while Cpk measures only spread
Cpk measures long-term capability while Cp measures short-term capability

Correct answer: Cpk accounts for process centering while Cp measures only spread relative to specification width

Cpk incorporates where the process mean sits relative to the specification limits, penalizing processes that are off-center. Cp only compares the process spread to the specification width, ignoring whether the process is centered — so two processes with identical Cp values can have very different Cpk values.

Question 62: Which metric represents the total number of defect opportunities per million in a process?

RTY
Cp
DPMO (Correct answer)
Cpk

Correct answer: DPMO

Defects Per Million Opportunities (DPMO) quantifies the defect rate normalized to one million opportunities, enabling comparison across different processes.

Question 63: A Green Belt uses a 'concentration diagram' during the Analyze phase. What information does this tool provide?

The correlation between two continuous variables
The proportion of defects attributable to each cause category
The physical location of defects on a unit or product map (Correct answer)
The statistical distribution of defect counts over time

Correct answer: The physical location of defects on a unit or product map

A concentration diagram overlays defect locations on a drawing or image of the unit to reveal spatial patterns in where defects occur.

Question 64: A Green Belt notices that defects spike every Monday morning on the assembly line. Which Analyze phase tool best captures this time-based pattern?

Regression analysis
Box plot
Control chart (Correct answer)
Scatter diagram

Correct answer: Control chart

Control charts plot data over time and reveal periodic patterns such as day-of-week effects.

Question 65: The rate at which products need to be completed to meet customer demand is one every 20 minutes. The total time from when an order is placed to when it is delivered is 4 days. The actual time spent working on one unit is 3 hours. Which of these represents the Takt Time?

3 hours
4 days
Cannot be determined
20 minutes (Correct answer)

Correct answer: 20 minutes

Takt time is the rate at which a finished product needs to be completed to meet customer demand. It's the 'heartbeat' of the production system. In this scenario, that rate is explicitly stated as one every 20 minutes. The 4 days is Lead Time, and the 3 hours is Cycle Time.

Question 66: A project team is struggling to narrow focus on what matters most to the customer. Which Define phase concept should they revisit?

Hypothesis testing
Design of experiments
Voice of the Customer (Correct answer)
Statistical process control

Correct answer: Voice of the Customer

Voice of the Customer captures customer expectations and preferences to guide project priorities.

Question 67: What is the purpose of the 'Is/Is Not' analysis tool in the Analyze phase?

To quantify the financial impact of each potential cause
To calculate the probability of defect occurrence
To map the process flow and identify non-value-added steps
To narrow down potential root causes by defining where the problem does and does not occur (Correct answer)

Correct answer: To narrow down potential root causes by defining where the problem does and does not occur

Is/Is Not analysis systematically scopes the problem by identifying boundaries where the issue exists versus where it does not.

Question 68: What is the primary purpose of conducting a pilot test before full-scale implementation of an improvement?

To validate the solution on a small scale and identify unforeseen issues (Correct answer)
To reduce the number of team members needed
To satisfy upper management requirements
To delay the project timeline

Correct answer: To validate the solution on a small scale and identify unforeseen issues

Pilot testing validates that a proposed solution works effectively on a limited scale before committing resources to full deployment.

Question 69: Which tool is used during the Define phase to visually map the customer's experience and identify pain points along their journey?

Pareto chart
Affinity diagram
Customer journey map (Correct answer)
Control chart

Correct answer: Customer journey map

A customer journey map traces each touchpoint a customer has with a process, highlighting where frustration or failure occurs.

Question 70: Which graphical tool displays the relationship between two continuous variables to identify correlation patterns?

Histogram
Scatter diagram (Correct answer)
Control chart
Pareto chart

Correct answer: Scatter diagram

A scatter diagram plots paired data points to visually reveal the direction and strength of correlation between two variables.

Question 71: Which of the eight wastes in Lean refers to producing more than the customer currently needs?

Overproduction (Correct answer)
Defects
Excess inventory
Waiting

Correct answer: Overproduction

Overproduction is considered the worst waste because it generates many of the other wastes, such as excess inventory and unnecessary transport.

Question 72: In the Improve phase, a Force Field Analysis is used primarily to:

Map all process inputs to their corresponding outputs
Identify and balance the driving forces and restraining forces surrounding a proposed change (Correct answer)
Calculate the return on investment for competing solutions
Determine the optimal factor settings through experimentation

Correct answer: Identify and balance the driving forces and restraining forces surrounding a proposed change

Force Field Analysis, developed by Kurt Lewin, visually separates the forces pushing toward a change (drivers) from those pushing against it (restrainers), helping the team plan how to amplify drivers and weaken barriers before implementation.

Question 73: During the Improve phase, what technique involves systematically testing multiple factors and their interactions to find optimal settings?

Regression analysis
Benchmarking
Failure Mode and Effects Analysis
Design of Experiments (DOE) (Correct answer)

Correct answer: Design of Experiments (DOE)

Design of Experiments (DOE) is a structured method for planning experiments to efficiently evaluate how multiple factors and their interactions affect a process output.

Question 74: In the 5S Lean framework, what does the third 'S' — 'Shine' — require teams to do?

Sustain improvements through regular audits and discipline
Establish visual standards and labels for all workstations
Sort items into keep, discard, or return categories
Clean the work area and inspect equipment during the cleaning process (Correct answer)

Correct answer: Clean the work area and inspect equipment during the cleaning process

'Shine' (Seiso) goes beyond basic cleaning — teams clean the workspace while simultaneously inspecting equipment for defects, leaks, or abnormalities, turning cleaning into a form of inspection.

Question 75: An X-bar and R chart is being used to monitor the average diameter of a machined part. The process owner observes six consecutive points trending downwards, but all points are still within the control limits. According to standard SPC rules, what is the correct interpretation?

The process is perfectly stable and requires no action.
The control limits should be immediately recalculated based on the new trend.
The measurement system is likely broken and must be replaced.
This pattern indicates a special cause of variation that should be investigated. (Correct answer)

Correct answer: This pattern indicates a special cause of variation that should be investigated.

In Statistical Process Control (SPC), certain patterns or 'runs' signal the presence of a special cause of variation, even if no points have crossed the control limits. A run of six or more consecutive points trending in the same direction is a classic rule indicating that a non-random factor is influencing the process, which warrants investigation.

Question 76: A DMAIC team wants to ensure their project scope is neither too broad nor too narrow. Which Define phase element addresses this?

Measurement system analysis
Regression analysis
Control chart
Project scope statement with clear boundaries (Correct answer)

Correct answer: Project scope statement with clear boundaries

The project scope statement defines what is included and excluded, preventing scope creep and ensuring focus.

Question 77: Which of the following scenarios best illustrates the Lean principle of 'Flow'?

Holding a weekly meeting to review production numbers and identify which departments are behind schedule.
Producing large batches of a product based on a quarterly sales forecast to minimize machine setup time.
A patient in a clinic is registered, immediately sees a nurse for triage, and is then placed directly into an examination room to see a doctor without returning to the waiting room. (Correct answer)
An assembly line where each station has a large buffer of inventory to ensure it never has to wait for parts from the previous station.

Correct answer: A patient in a clinic is registered, immediately sees a nurse for triage, and is then placed directly into an examination room to see a doctor without returning to the waiting room.

The principle of Flow is focused on creating a process where work moves smoothly and continuously from one value-adding step to the next without interruptions, delays, or back-tracking. The clinic scenario is the only one that describes an uninterrupted, smooth progression of the 'product' (the patient) through the process.

Question 78: What does 'mistake-proofing' (poka-yoke) primarily target in a process?

Reducing cycle time
Preventing defects by making errors impossible or immediately detectable (Correct answer)
Increasing production speed
Eliminating unnecessary process steps

Correct answer: Preventing defects by making errors impossible or immediately detectable

Poka-yoke devices are designed to prevent errors from occurring or to detect them immediately if they do occur.

Question 79: A Green Belt discovers that different customers have contradictory requirements for the same process output. What should be done first?

Delay the project until all customers agree
Escalate to the Champion to make the final decision
Choose the requirements of the largest customer segment
Segment customers and prioritize requirements using a Kano model or similar tool (Correct answer)

Correct answer: Segment customers and prioritize requirements using a Kano model or similar tool

Customer segmentation and prioritization tools like the Kano model help resolve conflicting requirements by identifying which needs are most critical to each group.

Question 80: A project benefit realization review is typically conducted to:

Decide whether to apply the project approach to other areas
Evaluate the quality of the control plan documentation
Confirm that the financial savings projected during the project were actually achieved (Correct answer)
Determine if the Green Belt should receive certification

Correct answer: Confirm that the financial savings projected during the project were actually achieved

A benefit realization review validates that the anticipated financial and operational benefits (savings, quality improvements) actually occurred after project implementation.

Question 81: In a measurement system analysis, a %Gage R&R of 28% is found. What action is most appropriate?

Immediately replace all measuring instruments
Accept the measurement system as fully adequate
Investigate improvement but proceed with caution (Correct answer)
Reject all data collected and restart

Correct answer: Investigate improvement but proceed with caution

A %Gage R&R between 10% and 30% is considered marginally acceptable; the team should work to improve the system but can proceed cautiously for some decisions.

Question 82: A project team is developing a high-level view of a process to understand its boundaries, stakeholders, and the flow of materials and information. They are identifying the suppliers, inputs, key process steps, outputs, and customers. Which tool are they using?

SIPOC Diagram (Correct answer)
Fishbone Diagram
Pareto Chart
Control Chart

Correct answer: SIPOC Diagram

A SIPOC diagram stands for Suppliers, Inputs, Process, Outputs, and Customers. It is a high-level process map used in the Define phase to provide a broad overview of a project, identify key stakeholders, and establish the project's scope before diving into a more detailed process map.

Question 83: Which tool is used in the Define phase to translate customer needs into specific, measurable requirements?

Fishbone diagram
Pareto chart
Control chart
Critical to Quality (CTQ) tree (Correct answer)

Correct answer: Critical to Quality (CTQ) tree

A CTQ tree translates broad customer needs into specific, measurable critical-to-quality requirements that the project must address.

Question 84: In a designed experiment, what is a 'confounded' effect?

An effect with a p-value greater than 0.05
Two or more effects that cannot be separately estimated because they are aliased (Correct answer)
An effect that has been statistically confirmed as significant
A factor that is held constant throughout the experiment

Correct answer: Two or more effects that cannot be separately estimated because they are aliased

Confounding (aliasing) occurs when two effects are mathematically indistinguishable from each other in a fractional factorial design.

Question 85: A Green Belt performs a one-way ANOVA and obtains an F-statistic with p = 0.001. What is the correct interpretation?

The variance within groups exceeds the variance between groups
All group means are equal
At least one group mean is significantly different from the others (Correct answer)
All groups have different means from each other

Correct answer: At least one group mean is significantly different from the others

A significant ANOVA F-test indicates that at least one group mean differs, but does not specify which groups differ.

Question 86: A project charter defines the problem statement, scope, goals, and team. Which element is most critical to include to ensure project boundaries are respected?

Team roles
Scope statement (Correct answer)
Business case
Milestone timeline

Correct answer: Scope statement

The scope statement explicitly defines what is included and excluded from the project, preventing scope creep and keeping the team focused on the right problem.

Question 87: In a DOE, a 'main effect' refers to:

The interaction between all factors simultaneously
The combined effect of two factors acting together
The average change in the response caused by changing one factor from low to high (Correct answer)
The unexplained variation in the experimental results

Correct answer: The average change in the response caused by changing one factor from low to high

A main effect is the average change in the response variable when a single factor moves from its low level to its high level, averaged across all levels of other factors.

Question 88: A Green Belt discovers through data analysis that the process mean has shifted over time but process spread remains constant. Which graphical tool would BEST confirm this finding?

Normal probability plot
Box plot comparing time periods
Multi-vari chart showing positional variation
I-MR chart showing a sustained shift in the individual values (Correct answer)

Correct answer: I-MR chart showing a sustained shift in the individual values

An I-MR (Individuals and Moving Range) control chart reveals a sustained shift in the process mean while the Moving Range chart confirms spread is stable.

Question 89: A project team is in the initial stage of a Six Sigma project to reduce patient waiting times at a clinic. They are creating a high-level process map that identifies suppliers, inputs, the key process steps, outputs, and customers. Which tool are they using?

Pareto Chart
SIPOC Diagram (Correct answer)
Control Chart
Fishbone Diagram

Correct answer: SIPOC Diagram

A SIPOC (Suppliers, Inputs, Process, Outputs, Customers) diagram is a high-level process mapping tool used in the Define phase to provide a broad overview of a process. It helps the team understand the project's scope and the key elements involved before diving into detailed analysis.

Question 90: A 5S implementation is underway. Which 'S' focuses on creating rules and schedules to maintain the improved workplace?

Sort
Standardize (Correct answer)
Shine
Set in Order

Correct answer: Standardize

Standardize (the 4th S) involves creating standards, procedures, and schedules that sustain the gains from the first three S activities.

Question 91: A Lean team uses a heijunka box to schedule work. What problem is heijunka designed to solve?

Excess inventory by reducing batch sizes to zero
Overproduction driven by push scheduling
Unevenness (Mura) in production by leveling type and volume (Correct answer)
Waiting waste by speeding up the slowest process step

Correct answer: Unevenness (Mura) in production by leveling type and volume

Heijunka (production leveling) smooths production volume and mix over time to reduce the peaks and valleys that create Mura and downstream stress.

Question 92: What distinguishes a business case from a problem statement in a Six Sigma project charter?

They are interchangeable sections that describe the same information in different formats
The business case defines the project scope; the problem statement defines the improvement goal
The business case identifies the root cause; the problem statement quantifies the defect rate
The business case justifies the financial and strategic value of the project; the problem statement describes what is wrong and its impact (Correct answer)

Correct answer: The business case justifies the financial and strategic value of the project; the problem statement describes what is wrong and its impact

A business case explains WHY the project deserves organizational resources by linking it to strategic or financial value, while the problem statement describes WHAT is wrong, how it is measured, and its impact — without proposing causes or solutions.

Question 93: From a Lean perspective, which of the following BEST defines a 'value-added' activity?

Any activity that takes a long time to complete and requires a high skill level.
Any activity that transforms the product or service and the customer is willing to pay for. (Correct answer)
Any activity that an internal manager deems important.
Any activity that is required by a regulatory body.

Correct answer: Any activity that transforms the product or service and the customer is willing to pay for.

The core principle of Lean is to define value from the customer's perspective. A value-added activity must meet three criteria: it transforms the product or service, the customer is willing to pay for it, and it's done right the first time.

Question 94: A Lean Six Sigma team has completed improvements and is closing the project. Which metric best indicates that gains have been sustained six months after handover?

The reduction in the number of control charts in use
The number of team members still engaged in the project
The project charter scope statement
The process sigma level remaining at or above the improved baseline (Correct answer)

Correct answer: The process sigma level remaining at or above the improved baseline

Sustained improvement is demonstrated by ongoing process performance data — specifically, the sigma level (or defect rate) remaining at or above the level achieved during the Improve phase, confirming the gains have held.

Question 95: Which statistical test should a Green Belt use to determine whether the mean output of Machine A is significantly different from Machine B?

ANOVA
Two-sample t-test (Correct answer)
Mood's median test
Chi-square test

Correct answer: Two-sample t-test

A two-sample t-test compares the means of two independent groups to determine statistical significance.

Question 96: In regression analysis during the Analyze phase, what does the R-squared value represent?

The slope of the regression line
The confidence interval width
The percentage of variation in the response variable explained by the predictor (Correct answer)
The correlation between residuals

Correct answer: The percentage of variation in the response variable explained by the predictor

R-squared indicates the proportion of variability in the dependent variable that is accounted for by the independent variable(s).

Question 97: A process has a mean of 50 and a standard deviation of 5. What is the coefficient of variation (CV)?

10% (Correct answer)
50%
25%
5%

Correct answer: 10%

CV = (standard deviation / mean) × 100 = (5/50) × 100 = 10%.

Question 98: Bias in a measurement system is best defined as:

The difference between the observed average measurement and the known reference (true) value (Correct answer)
The smallest detectable difference the gage can resolve
Inconsistency in measurements between different operators
Variation in measurements taken at different points across the measurement range

Correct answer: The difference between the observed average measurement and the known reference (true) value

Bias is the systematic offset between the average measured value and the true reference value, indicating a consistent over- or under-reading.

Question 99: A project team is working on improving the on-time delivery of a product. The Project Sponsor asks for the document that outlines the business case, problem statement, project scope, and key milestones. Which document should the Green Belt provide?

RACI Matrix
Project Charter (Correct answer)
Gantt Chart
Communication Plan

Correct answer: Project Charter

The Project Charter is the central document that contains all the elements requested by the Project Sponsor. It serves as the formal authorization and provides a high-level overview of the project, including the business case, problem statement, scope, goals, milestones, and team roles.

Question 100: What does SIPOC stand for in Lean Six Sigma?

Strategy, Implementation, Process, Outcomes, Control
Suppliers, Inputs, Process, Outputs, Customers (Correct answer)
Scope, Issues, Plan, Objectives, Constraints
Standards, Inputs, Procedures, Operations, Compliance

Correct answer: Suppliers, Inputs, Process, Outputs, Customers

SIPOC is a high-level process map identifying Suppliers, Inputs, Process steps, Outputs, and Customers.

Question 101: Which type of mistake-proofing device physically prevents a defect from being passed to the next step?

Control poka-yoke
Prediction poka-yoke
Warning poka-yoke
Detection poka-yoke (Correct answer)

Correct answer: Detection poka-yoke

A detection poka-yoke identifies a defect after it occurs and prevents it from moving forward, while a control (prevention) poka-yoke stops the defect from being made at all.

ASQ Certified Six Sigma Green Belt (CSSGB) Exam

The ASQ Certified Six Sigma Green Belt exam certifies professionals who are proficient in the core to advanced tools and techniques of Lean Six Sigma methodology.

100

Questions

240 min

Time Limit

55%

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