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EXIN LSSA Lean Six Sigma Yellow Belt study materials
EXIN LSSA Lean Six Sigma Yellow Belt study resources

EXIN LSSA Lean Six Sigma Yellow Belt practice questions

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Question 1Lean and Six Sigma fundamentals and concepts

In Lean terminology, which activity is classified as value-adding from the customer's perspective?

  1. A warehouse team moving finished goods between two storage areas
  2. An engineer rewriting a work instruction after an audit finding
  3. A machine operator tightening a bolt that the customer requires for the product to function Correct answer.
  4. An inspector re-checking a batch because the process is unstable

Explanation

Value-adding work is defined from the customer's viewpoint: it transforms the product or service in a way the customer is willing to pay for, and it is done right the first time. Tightening a required bolt changes the product into what the customer ordered, so it qualifies. Rework, inspection and internal movement do not change what the customer receives, so they are business-non-value-adding or pure waste.

Question 2Lean and Six Sigma fundamentals and concepts

A team lists the eight Lean wastes. Which item belongs to the waste called 'over-processing'?

  1. Producing 500 units when only 300 were ordered
  2. Waiting for a shared forklift to deliver raw material
  3. De-burring a part twice because two operations were never combined Correct answer.
  4. Storing semi-finished parts in a buffer between two cells

Explanation

Over-processing means doing more work on a product than the customer requires, such as duplicate steps, unnecessary polishing or redundant approvals. Performing the same de-burring operation twice because steps were never combined is the classic example. The other options describe waiting, overproduction and inventory respectively.

Question 3Lean and Six Sigma fundamentals and concepts

Which statement correctly describes the DMAIC sequence used in Six Sigma projects?

  1. Define, Measure, Analyse, Improve, Control Correct answer.
  2. Design, Measure, Assess, Implement, Certify
  3. Detect, Measure, Analyse, Implement, Confirm
  4. Define, Monitor, Adjust, Inspect, Close

Explanation

DMAIC is the standard Six Sigma roadmap for improving an existing process: Define the problem and scope, Measure current performance, Analyse root causes, Improve with countermeasures, then Control the gains. The other sequences are invented acronyms that do not match the methodology.

Question 4Lean and Six Sigma fundamentals and concepts

What is the primary purpose of a charter in a Lean Six Sigma improvement project?

  1. To capture the operator's standard work instructions for the cell
  2. To document the agreed problem, scope, goal, team and timeline before work begins Correct answer.
  3. To record every measurement collected during the measure phase
  4. To list the individual steps of the improved process after implementation

Explanation

The project charter is the contract between the team and the sponsor; it defines the problem statement, business case, scope boundaries, goal metrics, team roles and milestones. It is written before the project starts and is used to keep the work aligned. Measurement logs, future-state process maps and standard work documents are separate deliverables.

Question 5Lean and Six Sigma fundamentals and concepts

A process produces 40 defects across 2,000 opportunities. What is the defects per opportunity (DPO)?

  1. 0.02 Correct answer.
  2. 0.20
  3. 2.00
  4. 0.05

Explanation

DPO equals the number of defects divided by the number of opportunities, so 40 divided by 2,000 gives 0.02. It is a ratio between zero and one and is the input for converting to sigma level. Reading it as a percentage (2%) is the same result expressed differently, but the decimal form is the DPO value.

Question 6Lean and Six Sigma fundamentals and concepts

Which pair of metrics is used to describe process capability relative to specification limits?

  1. Cp and Cpk Correct answer.
  2. DPU and DPO
  3. MTBF and MTTR
  4. OEE and Takt

Explanation

Cp compares specification width with process spread, while Cpk also accounts for how well the process is centred within those limits. Together they express capability against customer specifications. DPU and DPO are defect rates, MTBF and MTTR are reliability measures, and OEE and takt relate to equipment effectiveness and demand pace.

Question 7Lean and Six Sigma fundamentals and concepts

A team maps a process and finds that a purchase order is approved by three managers in sequence, each checking the same figures. Which Lean action addresses this finding?

  1. Add a fourth approval to make the control stronger
  2. Eliminate the redundant approvals so one authorised check remains Correct answer.
  3. Ask the requester to re-enter the order data for each approval
  4. Move the three approvals into a single meeting to save travel time

Explanation

Duplicate checks that add no decision value are over-processing, and the Lean response is to simplify by removing the redundant steps while keeping one adequate control. Adding approvals or re-entering data increases waste. Gathering approvals in one meeting reduces some waiting but leaves the unnecessary work in place.

Question 8Lean and Six Sigma fundamentals and concepts

What does takt time represent in a Lean system?

  1. The total time a unit spends waiting in queues before shipment
  2. The average time between two consecutive machine breakdowns
  3. The fastest cycle a machine can achieve when running at maximum speed
  4. The available production time divided by customer demand in that period Correct answer.

Explanation

Takt time sets the pace of production to match customer demand: available working time divided by the number of units the customer requires. It is a target rhythm, not a measure of equipment speed. Cycle time is what the process actually achieves, and lead time covers the whole flow including waiting.

Question 9Lean and Six Sigma fundamentals and concepts

Which statement best captures the principle of 'pull' in a Lean value stream?

  1. A central planner issues a weekly schedule to every workstation regardless of use
  2. Downstream consumption signals upstream production, so work is triggered by actual need Correct answer.
  3. Buffer stock is increased at each stage so that no station ever starves
  4. Each station produces as much as it can to keep every operator fully occupied

Explanation

In a pull system, a downstream customer or process consumes output and that consumption authorises replenishment upstream, often through kanban signals. Production is triggered by real demand rather than forecast or local capacity. Push scheduling, maximum local output and large buffers all conflict with the pull principle.

Question 10Lean and Six Sigma fundamentals and concepts

A work cell has five stations with cycle times of 30, 45, 40, 50 and 35 seconds. Demand requires a takt time of 48 seconds. Which statement is true?

  1. The station at 30 seconds is the bottleneck because it finishes first
  2. Every station is comfortably below takt, so no change is needed
  3. The station at 50 seconds exceeds takt and is the constraint that must be improved Correct answer.
  4. Takt time must be raised to 50 seconds to match the slowest station

Explanation

Any station whose cycle time is longer than takt cannot keep up with customer demand and limits the line's output, so the 50-second station is the constraint. The 45-second station is close to takt but still within it. Improvement effort should first target the station above takt rather than the fastest one.

Question 11Lean and Six Sigma fundamentals and concepts

In a Lean Six Sigma context, what distinguishes 'common cause' variation from 'special cause' variation?

  1. Common cause variation appears only after a machine has broken down, while special cause variation is the normal noise of the process
  2. Common cause variation can be removed only by inspecting every unit produced
  3. Common cause variation is always larger in magnitude than special cause variation
  4. Common cause variation is inherent in the stable process, while special cause variation arises from an identifiable, unusual event Correct answer.

Explanation

Common cause variation comes from the many small, everyday sources built into a stable process and is reduced by changing the system. Special cause variation is signalled by unusual patterns on a control chart and traces to a specific assignable event. Confusing the two leads to tampering with stable processes or blaming operators for system problems.

Question 12Lean and Six Sigma fundamentals and concepts

What is the main purpose of a control chart in the control phase of a DMAIC project?

  1. To calculate the return on investment of the improvement
  2. To rank customer requirements by importance for the design team
  3. To display the project budget against actual spending over time
  4. To separate normal process noise from signals of a real shift so the team knows when to act Correct answer.

Explanation

A control chart plots a process measure over time with statistically derived limits, allowing the team to distinguish routine variation from signals that something has changed. Acting only on genuine signals prevents tampering. Budget tracking, requirement ranking and financial return are handled by other tools.

Question 13Lean and Six Sigma fundamentals and concepts

A team wants to show the frequency of different defect categories so it can focus on the largest contributors. Which tool is most appropriate?

  1. Scatter diagram
  2. Affinity diagram
  3. Pareto chart Correct answer.
  4. Control chart

Explanation

A Pareto chart ranks defect categories by frequency in descending bars with a cumulative line, making it easy to see which few categories account for most of the problem. A scatter diagram tests relationships between two variables, a control chart tracks variation over time, and an affinity diagram organises qualitative ideas.

Question 14Lean and Six Sigma fundamentals and concepts

During the measure phase, a team collects data by having operators record every defect they notice during a shift. What is the biggest risk to data validity in this approach?

  1. Operator judgement and inconsistent definitions make the recorded defects unreliable Correct answer.
  2. The data will always show a decreasing trend over time
  3. The sample size will automatically be too small to analyse
  4. Control charts cannot be applied to data collected by operators

Explanation

When people decide subjectively what counts as a defect, results vary between operators and shifts unless there is an operational definition and calibration. Measurement system analysis exists to quantify this risk. Sample size depends on the collection plan, control charts can use such data, and no automatic trend is created.

Question 15Lean and Six Sigma fundamentals and concepts

Which tool would a team use to generate and group a large number of ideas about possible causes of a problem before narrowing them down?

  1. A process capability study
  2. Brainstorming with an affinity diagram Correct answer.
  3. A control plan
  4. A run chart of the output measure

Explanation

Brainstorming produces many candidate causes, and an affinity diagram groups them into themes so the team can prioritise. A run chart shows performance over time, a capability study compares spread with specifications, and a control plan documents how gains will be sustained; none of these generates and organises ideas.

Question 16Lean and Six Sigma fundamentals and concepts

A team builds a cause-and-effect diagram. Which set of categories matches the classic '6M' structure?

  1. Man, Machine, Material, Method, Measurement, Mother Nature Correct answer.
  2. Man, Money, Market, Machine, Method, Management
  3. Material, Method, Market, Measure, Machine, Motivation
  4. Man, Machine, Material, Metric, Model, Milestone

Explanation

The 6M cause-and-effect framework groups possible causes under Man, Machine, Material, Method, Measurement and Mother Nature (environment). It provides a structured prompt so the team considers all major source families. The other lists mix in categories such as money, market or milestones that are not part of the framework.

Question 17Lean and Six Sigma fundamentals and concepts

Which statement correctly describes the '5 Whys' technique?

  1. It requires five separate improvement projects before a result is expected
  2. It measures a process at five points to estimate its variation
  3. It asks five different people for their opinion on the same problem
  4. It repeatedly asks why a problem occurs to drill from symptoms toward a root cause Correct answer.

Explanation

The 5 Whys is a simple root-cause technique in which each answer to 'why' becomes the subject of the next question, moving the team from the visible symptom toward the underlying cause. The number five is a guide rather than a fixed rule. It is not a survey, a project count or a sampling method.

Question 18Lean and Six Sigma fundamentals and concepts

A process has a stable, normally distributed output with a mean of 100 and a standard deviation of 2. The lower specification limit is 94. What is the Cpk relative to that limit?

  1. 0.5
  2. 1.0 Correct answer.
  3. 3.0
  4. 2.0

Explanation

Cpk for a single limit is the distance from the mean to the nearest specification limit divided by three standard deviations. Here 100 minus 94 is 6, and three standard deviations is 6, so Cpk is 1.0. A value of 1.0 means the limit sits three sigma from the mean.

Question 19Lean and Six Sigma fundamentals and concepts

What is the primary role of a Yellow Belt in a Lean Six Sigma organisation?

  1. To lead complex cross-functional projects and mentor Black Belts
  2. To participate as a team member and apply basic tools within their own work area Correct answer.
  3. To audit other departments against ISO quality standards
  4. To approve project charters and allocate organisational budgets

Explanation

Yellow Belts are trained in the fundamentals and typically contribute as team members, gather data and apply simple tools in their own processes. Leading complex projects is the role of Green and Black Belts, while charter approval and budgeting belong to sponsors and leadership. Standards auditing is a separate quality function.

Question 20Lean and Six Sigma fundamentals and concepts

Which element is essential to standard work?

  1. A defined sequence of steps with specified cycle times and documented work content Correct answer.
  2. A schedule of upcoming management meetings
  3. A forecast of next year's customer demand
  4. A list of every defect found in the last month

Explanation

Standard work captures the current best method: the sequence of steps, the time each takes and the work content, so the process can be repeated consistently and improved from a known baseline. Defect lists, meeting schedules and demand forecasts are unrelated records. Without a defined standard, variation cannot be controlled or reduced.

Question 21Lean and Six Sigma fundamentals and concepts

A value stream map shows a process with a total lead time of 12 days and actual processing time of 40 minutes. What does this reveal?

  1. The team should increase batch sizes to reduce the processing time
  2. The value stream map must be wrong, since lead time cannot exceed processing time
  3. Most of the lead time is waiting between steps, which is the main improvement opportunity Correct answer.
  4. The process is already highly efficient because processing time is short

Explanation

Lead time includes queueing and waiting as well as processing, so a large gap between them signals inventory and delay between steps. In this case roughly 11 days and more of the 12-day lead time is non-value-adding waiting. Reducing queues and batch sizes is the usual Lean response.

Question 22Lean and Six Sigma fundamentals and concepts

Which situation best illustrates the Lean principle of 'flow'?

  1. Work-in-process inventory is maximised so that every station has a backlog
  2. A product moves continuously through co-located steps with minimal queueing between them Correct answer.
  3. Products are stored in a central warehouse until a customer order arrives
  4. Each department completes a full batch before passing it to the next department

Explanation

Flow means work moves smoothly from step to step without stopping, waiting or accumulating in queues, which shortens lead time and exposes problems. Batch-and-queue transfer, large buffers and central storage all interrupt flow. Creating continuous flow often begins with co-locating or linking process steps.

Question 23Lean and Six Sigma fundamentals and concepts

A team plots weekly defect counts on a run chart for 20 weeks and sees seven consecutive points below the median. How should this be interpreted?

  1. It is normal random variation and should be ignored
  2. It proves the process is now perfect and monitoring can stop
  3. The pattern suggests a non-random shift that warrants investigation of what changed Correct answer.
  4. It indicates that the median should be recalculated every week

Explanation

A run of seven or more points on the same side of the median is a recognised signal of non-random behaviour, suggesting the process has shifted. The appropriate response is to investigate what changed rather than dismiss or over-interpret the pattern. Even a positive shift does not justify stopping monitoring.

Question 24Lean and Six Sigma fundamentals and concepts

What is the purpose of a kanban signal in a pull system?

  1. To schedule preventive maintenance on a machine
  2. To document the training records of each operator
  3. To record the number of defects detected at final inspection
  4. To authorise replenishment or production of a defined quantity when a downstream use occurs Correct answer.

Explanation

A kanban is a visual or electronic signal that authorises upstream work or replenishment once downstream consumption has occurred, keeping inventory limited and linked to actual need. It is not a quality record or an administrative file. Maintenance scheduling and defect tracking use separate systems.

Question 25Lean and Six Sigma fundamentals and concepts

A project team finds that two candidate causes each appear plausible, so they plan to confirm which one actually drives the defect rate. Which approach best fits the analyse phase?

  1. Implement countermeasures for both causes at once and see what happens
  2. Choose the cause favoured by the most senior team member and implement a fix
  3. Close the project because the cause cannot be determined
  4. Collect data on both variables and test their statistical relationship with the defect rate Correct answer.

Explanation

The analyse phase requires evidence that a suspected cause is genuinely linked to the effect, typically through data collection and hypothesis testing or graphical analysis. Implementing changes without verification risks wasted effort and confounded results. Seniority and simultaneous fixes do not establish causality.

Question 26Lean and Six Sigma fundamentals and concepts

In Lean Six Sigma, what does the abbreviation 'DMAIC' stand for?

  1. Define, Monitor, Adjust, Inspect, Correct
  2. Document, Measure, Analyse, Implement, Certify
  3. Define, Measure, Analyse, Improve, Control Correct answer.
  4. Design, Manage, Assess, Implement, Check

Explanation

DMAIC is the five-phase improvement cycle used for improving existing processes: Define, Measure, Analyse, Improve, and Control. It provides a structured roadmap for problem-solving and is a core concept in Lean Six Sigma.

Question 27Lean and Six Sigma fundamentals and concepts

Which of the following is an example of waste (muda) in a Lean context?

  1. A team conducting a gemba walk to observe the process
  2. A machine producing parts faster than the next process can use them Correct answer.
  3. A kanban card signalling the need for replenishment
  4. An operator following a standard work instruction

Explanation

Overproduction is one of the seven wastes in Lean; producing faster than downstream demand creates excess inventory and other hidden problems. Gemba walks, standard work, and kanban are Lean practices, not wastes.

Question 28Lean and Six Sigma fundamentals and concepts

A team is analysing a process and wants to determine the relationship between two continuous variables, such as temperature and yield. Which tool is most appropriate?

  1. Pareto chart
  2. Control chart
  3. Scatter diagram Correct answer.
  4. Check sheet

Explanation

A scatter diagram plots one variable against another to reveal correlation or relationship patterns. Pareto charts prioritise categories, control charts monitor stability over time, and check sheets collect data, but none directly show the relationship between two continuous variables.

Question 29Lean and Six Sigma fundamentals and concepts

In a Lean Six Sigma project, what is the primary purpose of a project charter?

  1. To formally authorise the project and define its scope, goals, and boundaries Correct answer.
  2. To list all potential causes of the problem for later analysis
  3. To document the standard operating procedure for the improved process
  4. To record the detailed data collected during the measure phase

Explanation

The project charter is a document that authorises the project, clarifies the problem statement, goals, scope, and team roles. It is created during the Define phase and serves as a contract between the team and stakeholders.

Question 30Lean and Six Sigma fundamentals and concepts

A process has a stable and normally distributed output with a mean of 50 and a standard deviation of 2. The upper specification limit is 56. What is the process capability index (Cp)?

  1. 1.0 Correct answer.
  2. 1.5
  3. 2.0
  4. 0.67

Explanation

Cp = (USL - LSL) / (6σ). Assuming a symmetric specification with LSL = 44 (since the mean is 50 and USL is 56), Cp = (56 - 44) / (6 * 2) = 12 / 12 = 1.0. This indicates the process spread exactly matches the specification width.

Question 31The DMAIC improvement cycle

In the DMAIC cycle, which phase immediately follows the Define phase?

  1. Analyze
  2. Improve
  3. Control
  4. Measure Correct answer.

Explanation

DMAIC is a fixed sequence: Define, Measure, Analyze, Improve, Control. After the problem and goals are defined, the team must quantify current performance, which happens in Measure. Control comes last and Analyze follows Measure, so neither can be the immediate successor of Define.

Question 32The DMAIC improvement cycle

A team has finished verifying the root cause of excessive invoice errors and now wants to select and pilot a countermeasure. Which DMAIC phase are they entering?

  1. Measure
  2. Control
  3. Improve Correct answer.
  4. Define

Explanation

Selecting, testing and piloting countermeasures is the core work of the Improve phase. Root-cause verification closes Analyze, and the team moves into Improve to design and trial solutions. Define and Measure come earlier and Control comes after the solution is proven.

Question 33The DMAIC improvement cycle

What is the primary purpose of a project charter in the Define phase?

  1. To record the measurement system analysis results
  2. To calculate process capability indices
  3. To list every possible root cause for later testing
  4. To authorize the project and document problem, scope, goals and team Correct answer.

Explanation

The charter is the formal authorization document that captures the business case, problem statement, scope, objectives, team and timeline. It gives the team a mandate and protects scope. Measurement and capability data belong to Measure, and cause lists belong to Analyze.

Question 34The DMAIC improvement cycle

A team writes a problem statement reading: 'The order-entry department is bad and should be fixed.' Which Define-phase weakness is most evident?

  1. It contains too many measurable targets
  2. It specifies the root cause too precisely
  3. It commits the team to a solution prematurely
  4. It lacks a measurable gap, location and time frame Correct answer.

Explanation

A sound problem statement quantifies the gap between current and expected performance and states where and when it occurs. This statement is vague and emotional, with no metric, baseline or time reference. It does not over-specify causes or solutions; it simply lacks measurable substance.

Question 35The DMAIC improvement cycle

During Measure, a team finds that two operators record the same dimension with consistently different results. Which Measure-phase activity addresses this?

  1. A stakeholder communication plan
  2. A failure mode and effects analysis
  3. A measurement system analysis Correct answer.
  4. A control chart on the improved process

Explanation

Measurement system analysis, often a gauge R&R study, quantifies variation from operators, equipment and repeatability. If operators differ systematically, the data cannot be trusted until the measurement system is corrected. FMEA and control charts belong to later phases and communication planning to Define or Control.

Question 36The DMAIC improvement cycle

Which pair of metrics is most appropriate for establishing the baseline in the Measure phase?

  1. Number of team meetings and project budget spent
  2. Control chart rules and reaction plans
  3. Defect rate and process cycle time Correct answer.
  4. Number of root causes and countermeasures chosen

Explanation

Measure establishes a performance baseline using process and quality metrics such as defect rate, yield, cycle time or cost of poor quality. These are quantifiable outputs of the process being studied. Meeting counts, cause lists and reaction plans are project or later-phase artifacts, not process baselines.

Question 37The DMAIC improvement cycle

In the Analyze phase, why is data stratification useful?

  1. It guarantees that the process is in statistical control
  2. It replaces the need for a problem statement
  3. It breaks aggregate data into subgroups to reveal hidden patterns Correct answer.
  4. It removes the need for a hypothesis test

Explanation

Stratification splits data by factors such as shift, machine, operator or product type so differences hidden in the aggregate become visible. This often pinpoints where variation concentrates. It does not eliminate statistical testing, prove control, or substitute for the charter.

Question 38The DMAIC improvement cycle

A team plots defect counts by machine and by shift and finds that defects cluster on one machine during one shift. What is the most appropriate next step in Analyze?

  1. Move directly to the Control phase
  2. Verify the suspected cause with further data before improving Correct answer.
  3. Immediately purchase a replacement machine
  4. Rewrite the project charter to exclude that machine

Explanation

A pattern in stratified data is a clue, not proof; the team should confirm the suspected cause with additional data or a formal test before acting. This prevents implementing a countermeasure on a false signal. Purchasing equipment or skipping phases would be premature, and narrowing scope to hide the problem is improper.

Question 39The DMAIC improvement cycle

Which tool is most characteristic of the Analyze phase when a team wants to separate the vital few causes from the trivial many?

  1. Project charter
  2. Pareto chart Correct answer.
  3. Standard operating procedure
  4. Control plan

Explanation

A Pareto chart ranks causes by frequency or impact, applying the 80/20 principle to focus effort on the vital few. It is a classic Analyze-phase prioritization tool. Charters belong to Define, while control plans and SOPs are Control-phase documents.

Question 40The DMAIC improvement cycle

What distinguishes the Improve phase from the Analyze phase in DMAIC?

  1. Improve documents the as-is process map only
  2. Improve proves which cause is statistically significant
  3. Improve generates, selects and pilots changes to the process Correct answer.
  4. Improve establishes the measurement system

Explanation

Analyze identifies and verifies root causes; Improve then develops, selects, tests and pilots countermeasures that address those causes. Statistical confirmation of causes is Analyze work, and process mapping and measurement setup occur earlier.

Question 41The DMAIC improvement cycle

Before full implementation, a team runs a countermeasure on a single production line for two weeks. What is this activity called and why is it done?

  1. A pilot, to test feasibility and estimate effects with limited risk Correct answer.
  2. A gauge R&R, to validate measurement variation
  3. A control plan, to standardize the final method
  4. A stakeholder analysis, to map influence and interest

Explanation

Piloting tests a countermeasure on a limited scale so the team can confirm it works, catch side effects and estimate benefits before committing resources. It limits risk if the change fails. Control plans, gauge studies and stakeholder analysis serve different purposes in other phases.

Question 42The DMAIC improvement cycle

A team is choosing among several countermeasures. Which approach best reflects Lean Six Sigma practice in Improve?

  1. Choose the first idea suggested in brainstorming
  2. Score options against criteria such as impact, cost and ease of implementation Correct answer.
  3. Select the most expensive option to show commitment
  4. Defer the decision until after the Control phase

Explanation

Improve-phase selection uses structured evaluation, often a criteria matrix weighing expected impact against cost, risk and ease of implementation. This makes trade-offs explicit and defensible. Cost alone, first-idea bias or postponing the choice all undermine the phase.

Question 43The DMAIC improvement cycle

Which element is essential in a Control plan?

  1. A list of every countermeasure that was rejected
  2. The names of all suppliers in the supply chain
  3. The original brainstorming notes from Analyze
  4. The monitored metric, target, frequency, owner and reaction to out-of-control signals Correct answer.

Explanation

A control plan specifies what is monitored, the target or specification, how often, who is responsible, and what corrective action follows an out-of-spec or out-of-control signal. This sustains the gains after the project closes. Rejected ideas, raw notes and supplier lists are not core elements.

Question 44The DMAIC improvement cycle

After implementing a fix, a team plots daily defect rates on a control chart and sees a stable, lower level. What does this indicate about the Control phase?

  1. The project must return to the Define phase
  2. The countermeasure has failed and must be removed
  3. The data are invalid because variation is present
  4. The improvement is sustained and the process is predictable at the new level Correct answer.

Explanation

A stable control chart at a lower average shows the improved process is predictable and the gain is holding. Some common-cause variation is normal and expected. Returning to Define or removing the fix would be unjustified, and variation alone does not invalidate data.

Question 45The DMAIC improvement cycle

What is the main purpose of standardizing the improved method in the Control phase?

  1. To create work for the documentation team
  2. To replace the need for monitoring metrics
  3. To lock in the gain so the old method cannot easily return Correct answer.
  4. To increase the number of process steps

Explanation

Standardization documents the new method so everyone performs it consistently, preventing drift back to the old way. It supports sustained gains and complements, rather than replaces, ongoing monitoring. Adding steps or creating documentation work are not goals.

Question 46The DMAIC improvement cycle

A project team cannot get reliable data because the process records are incomplete. Which phase is most directly affected, and what is the consequence for DMAIC?

  1. Control, because reaction plans cannot be written
  2. Define, because the charter cannot be signed
  3. Improve, because no countermeasures can be brainstormed
  4. Measure, because no valid baseline can be established Correct answer.

Explanation

Measure depends on trustworthy data to establish the baseline and characterize variation. If records are incomplete, the baseline is unreliable and later Analyze conclusions are weakened. The charter can still be signed, and brainstorming or reaction planning is not the immediate blocker.

Question 47The DMAIC improvement cycle

A team wants to confirm that a suspected input variable actually influences the output before spending money on a fix. Which Analyze-phase technique fits best?

  1. A stakeholder communication matrix
  2. A control plan revision
  3. A project charter update
  4. A hypothesis test comparing output across input settings Correct answer.

Explanation

Hypothesis testing, such as a two-sample or ANOVA comparison, assesses whether output differences across input settings are statistically meaningful or due to chance. This confirms or rejects the suspected cause before investment. Charter updates, control plans and communication matrices do not test causal relationships.

Question 48The DMAIC improvement cycle

Which sequence correctly orders the deliverables produced across DMAIC?

  1. Pilot results, problem statement, baseline data, control plan
  2. Control plan, problem statement, root cause verification, pilot results
  3. Problem statement, baseline data, verified root cause, pilot results, control plan Correct answer.
  4. Baseline data, problem statement, control plan, verified root cause

Explanation

Each phase produces a characteristic deliverable in order: Define yields the problem statement, Measure the baseline, Analyze the verified root cause, Improve the piloted solution, and Control the control plan. Any other ordering places a later deliverable before its prerequisite phase.

Question 49The DMAIC improvement cycle

At a phase-gate review after Analyze, the sponsor asks the team to prove the project is ready to move on. Which evidence best supports the gate decision?

  1. The charter has been signed by the sponsor
  2. The team has brainstormed many possible solutions
  3. The control chart shows the process is stable at the improved level
  4. Root causes are verified with data and linked to the problem statement Correct answer.

Explanation

An Analyze gate is passed when the verified root causes are supported by data and clearly explain the problem defined in the charter. This justifies proceeding to solution design. Brainstormed solutions belong to Improve, an improved stable chart to Control, and the signed charter to the Define gate.

Question 50The DMAIC improvement cycle

Which statement best describes how DMAIC treats the relationship between Define and Control?

  1. Define and Control both focus on measuring process capability
  2. Control repeats the Define phase to restart the cycle
  3. Define and Control are optional phases in Lean Six Sigma
  4. Define sets the problem and goals, while Control sustains the gains against those goals Correct answer.

Explanation

Define frames the problem and target, and Control ensures the achieved improvement is maintained and monitored against that target. The two phases bracket the cycle. Capability measurement belongs to Measure, and neither phase is optional in DMAIC.