Lean Six Sigma Yellow Belt Certification Basic 5 — Questions and Answers
Question 1: What is 'takt time' in Lean manufacturing?
- The actual time it takes to complete one unit
- The available production time divided by customer demand rate (Correct answer)
- The maximum capacity of the slowest machine
- The time lost due to equipment breakdowns
Correct answer: The available production time divided by customer demand rate
Takt time is the rate at which products must be completed to meet customer demand, calculated as available time divided by demand.
Question 2: A process is said to be 'in statistical control' when:
- All output meets customer specifications
- Only common cause variation is present (Correct answer)
- The Cp index is greater than 1.33
- All defects have been eliminated
Correct answer: Only common cause variation is present
A process in statistical control exhibits only common cause (random) variation with no special causes present.
Question 3: Which of the following is an example of 'over-processing' waste in Lean?
- Storing excess raw materials in a warehouse
- Performing inspection steps the customer doesn't require or value (Correct answer)
- Moving finished goods across the facility
- Waiting for a machine to complete its cycle
Correct answer: Performing inspection steps the customer doesn't require or value
Over-processing means doing more work or adding more features than the customer requires or is willing to pay for.
Question 4: The 'Improve' phase of DMAIC involves:
- Defining the problem and project goals
- Developing and implementing solutions to address root causes (Correct answer)
- Monitoring the process with control charts post-implementation
- Collecting and analyzing baseline data
Correct answer: Developing and implementing solutions to address root causes
The Improve phase generates, selects, and pilots solutions that address the verified root causes identified in the Analyze phase.
Question 5: Voice of the Customer (VOC) data is most commonly gathered through:
- Reviewing internal process metrics and dashboards
- Surveys, interviews, focus groups, and complaint data (Correct answer)
- Conducting time studies on the production floor
- Analyzing financial reports and cost data
Correct answer: Surveys, interviews, focus groups, and complaint data
VOC is collected directly from customers using surveys, interviews, focus groups, and complaint analysis to understand their needs.
Question 6: A scatter diagram is used to:
- Rank defect categories from most to least frequent
- Explore the relationship between two variables (Correct answer)
- Track process performance over time
- Break down a problem into its root causes
Correct answer: Explore the relationship between two variables
A scatter diagram plots two variables on x and y axes to visually reveal whether a correlation or relationship exists.
Question 7: Which statement best describes 'special cause' variation?
- Variation that is inherent to the process and always present
- Variation caused by unusual, identifiable factors outside the normal process (Correct answer)
- Variation that can never be reduced or eliminated
- Variation within the customer's specification limits
Correct answer: Variation caused by unusual, identifiable factors outside the normal process
Special cause variation arises from specific, identifiable events or factors that are not part of the normal process.
Lean Six Sigma Yellow Belt Certification Basic 5
What is 'takt time' in Lean manufacturing?