Lean Six Sigma Yellow Belt Certification The Measure Phase 5 — Questions and Answers
Question 1: Which data collection technique involves observing the actual process in real time rather than relying on historical records?
- Retrospective data mining
- Direct observation (gemba) (Correct answer)
- Survey method
- Document review
Correct answer: Direct observation (gemba)
Direct observation (going to the gemba, or actual workplace) captures what truly happens rather than what historical records or memory suggest.
Question 2: A check sheet is most useful in the Measure phase for:
- Calculating sigma levels automatically
- Systematically collecting and tallying defect or event data in real time (Correct answer)
- Mapping the process flow
- Identifying root causes of variation
Correct answer: Systematically collecting and tallying defect or event data in real time
A check sheet is a structured form for collecting and organizing data at the source, making tallying and pattern recognition easy.
Question 3: In a SIPOC diagram, what does the 'O' represent?
- Operations
- Outputs (Correct answer)
- Opportunities
- Objectives
Correct answer: Outputs
In SIPOC (Suppliers, Inputs, Process, Outputs, Customers), 'O' stands for Outputs — the products, services, or information produced by the process.
Question 4: Which control chart is appropriate for monitoring the average and variation of a continuous measurement when subgroup size is 5?
- p-chart and c-chart
- X-bar and R chart (Correct answer)
- I-MR chart
- u-chart and np-chart
Correct answer: X-bar and R chart
The X-bar and R chart monitors subgroup means (X-bar) and subgroup ranges (R) for continuous data with subgroup sizes typically between 2 and 10.
Question 5: What is the purpose of calculating 'rolled throughput yield' (RTY) in the Measure phase?
- To determine the selling price of the product
- To measure the probability that a unit passes through all process steps without any defects (Correct answer)
- To count the total number of defects per unit
- To calculate the cost of raw materials
Correct answer: To measure the probability that a unit passes through all process steps without any defects
RTY is the product of first-pass yields at each process step, revealing the true probability a unit is completed defect-free without rework.
Question 6: When a team notices that measurements drift upward over the course of a shift, this is an example of measurement system:
- Linearity error
- Stability (drift) error (Correct answer)
- Repeatability error
- Reproducibility error
Correct answer: Stability (drift) error
Stability (or drift) refers to changes in a measurement system's bias over time, often caused by tool wear, temperature changes, or calibration drift.
Question 7: Which of the following is NOT a common source of variation that a cause-and-effect (fishbone) diagram would explore in the Measure phase?
- Man (people)
- Machine (equipment)
- Method (process)
- Market (competition) (Correct answer)
Correct answer: Market (competition)
The standard 6M categories of a fishbone diagram are Man, Machine, Method, Material, Measurement, and Mother Nature (environment) — not Market.
Lean Six Sigma Yellow Belt Certification The Measure Phase 5
Which data collection technique involves observing the actual process in real time rather than relying on historical records?