Lean Six Sigma Yellow Belt Certification Assessment 5 — Questions and Answers
Question 1: During an assessment, a team discovers that operators interpret work instructions differently. Which type of variation does this represent?
- Common cause variation
- Special cause variation (Correct answer)
- Inherent process variation
- Measurement system variation
Correct answer: Special cause variation
Different operator interpretations are assignable (special cause) variations that can be identified and eliminated, unlike random common cause variation.
Question 2: A process assessment reveals a defect rate of 3.4 DPMO. What sigma level does this correspond to?
- 3 Sigma
- 4 Sigma
- 5 Sigma
- 6 Sigma (Correct answer)
Correct answer: 6 Sigma
3.4 DPMO is the benchmark for Six Sigma performance, meaning nearly perfect quality with only 3.4 defects per million opportunities.
Question 3: What is the purpose of stratification in data collection during a Lean Six Sigma assessment?
- To randomly sample data from the process
- To separate data into subgroups to identify patterns or differences between groups (Correct answer)
- To calculate the mean and standard deviation
- To control the process using statistical limits
Correct answer: To separate data into subgroups to identify patterns or differences between groups
Stratification breaks data into meaningful subgroups (by shift, machine, operator) so the team can pinpoint which subgroup is driving a problem.
Question 4: Which assessment activity involves team members observing the actual workplace to see waste and problems firsthand?
- Benchmarking
- Gemba walk (Correct answer)
- FMEA review
- Regression analysis
Correct answer: Gemba walk
A Gemba walk involves going to the actual place where work is done to observe processes directly, rather than relying solely on reports or data.
Question 5: A team assessing a call center process finds that average handle time has increased over the past month. Which chart would best confirm if this is a statistically significant shift?
- Histogram
- Pareto chart
- Individuals (I-MR) control chart (Correct answer)
- Scatter diagram
Correct answer: Individuals (I-MR) control chart
An Individuals and Moving Range (I-MR) control chart plots time-ordered data with control limits, making it possible to detect statistically significant shifts or trends.
Question 6: In a Lean Six Sigma assessment, what does 'First Pass Yield' (FPY) measure?
- The percentage of products that require rework before passing final inspection
- The percentage of units that complete a process step correctly the first time without rework (Correct answer)
- The overall defect rate at the end of the production line
- The number of units produced per hour
Correct answer: The percentage of units that complete a process step correctly the first time without rework
FPY measures the proportion of units that pass through a process step without any defect, rework, or scrap on the first attempt.
Question 7: A Yellow Belt team is assessing the relationship between oven temperature and product hardness. Which tool is most appropriate to evaluate this relationship?
- Control chart
- Cause-and-effect diagram
- Scatter diagram (Correct answer)
- Check sheet
Correct answer: Scatter diagram
A scatter diagram plots two variables against each other to visually assess whether a correlation exists between them.
Lean Six Sigma Yellow Belt Certification Assessment 5
During an assessment, a team discovers that operators interpret work instructions differently.
Which type of variation does this represent?