Certified Six Sigma Black Belt Exam Trivia 5 — Questions and Answers
Question 1: The concept of 'Takt Time' in lean manufacturing is calculated as:
- Total production time divided by number of workers
- Available production time divided by customer demand rate (Correct answer)
- Cycle time multiplied by number of operations
- Defect rate divided by total units produced
Correct answer: Available production time divided by customer demand rate
Takt time = Available production time ÷ Customer demand rate; it sets the pace of production to match customer demand.
Question 2: Which Six Sigma chart is most appropriate for monitoring the proportion of defective items in large, variable-sized samples?
- X-bar and R chart
- p-chart (Correct answer)
- c-chart
- EWMA chart
Correct answer: p-chart
The p-chart monitors the proportion (fraction) of defective items in samples of varying size, making it appropriate for attribute data with variable subgroup sizes.
Question 3: In the context of Six Sigma, 'rolled throughput yield' (RTY) measures:
- Final yield at the last process step
- Probability that a unit passes through all process steps without any defect (Correct answer)
- Total number of defects divided by total opportunities
- Yield adjusted for rework and scrap costs
Correct answer: Probability that a unit passes through all process steps without any defect
RTY is the product of individual step yields across all process steps — it reflects the true probability of producing a defect-free unit end-to-end without any rework.
Question 4: Which executive at General Electric is most famous for championing Six Sigma in the 1990s and making it a corporate standard?
- Jack Welch (Correct answer)
- Jeff Immelt
- Larry Bossidy
- Bob Galvin
Correct answer: Jack Welch
Jack Welch, GE's CEO from 1981–2001, mandated Six Sigma across all GE businesses in 1995, making it the most visible corporate Six Sigma deployment of the era.
Question 5: A 'fishbone diagram' is also commonly known as which of the following?
- Scatter diagram
- Cause-and-effect diagram (Correct answer)
- Affinity diagram
- Tree diagram
Correct answer: Cause-and-effect diagram
A fishbone diagram is formally called a cause-and-effect diagram (also an Ishikawa diagram), with the 'fishbone' name coming from its branching visual shape.
Question 6: In statistical process control, the 'Western Electric Rules' are used to:
- Calculate control chart limits
- Detect non-random patterns indicating special cause variation (Correct answer)
- Determine minimum sample sizes
- Calibrate measurement equipment
Correct answer: Detect non-random patterns indicating special cause variation
The Western Electric Rules are a set of decision rules applied to control charts to detect non-random patterns that signal special cause (assignable cause) variation beyond just points outside control limits.
Question 7: What does 'COPQ' stand for in Six Sigma financial analysis?
- Cost of Poor Quality (Correct answer)
- Control of Process Quality
- Cycle of Process Quantification
- Cost of Process Quality
Correct answer: Cost of Poor Quality
COPQ — Cost of Poor Quality — quantifies the financial impact of defects, including internal failure costs (scrap, rework), external failure costs (warranties, returns), and appraisal costs.
Certified Six Sigma Black Belt Exam Trivia 5
The concept of 'Takt Time' in lean manufacturing is calculated as: