Certified Six Sigma Black Belt Exam Certified Six Sigma Black Belt Basic 1 — Questions and Answers
Question 1: Which tool is used to prioritize potential causes of a problem by separating the 'vital few' from the 'trivial many'?
- Fishbone diagram
- Pareto chart (Correct answer)
- Control chart
- Scatter diagram
Correct answer: Pareto chart
A Pareto chart applies the 80/20 rule to rank causes by frequency or impact, allowing teams to focus improvement efforts on the few causes responsible for most of the problem.
Question 2: In the DMAIC methodology, during which phase would a team establish baseline process performance metrics?
- Define
- Measure (Correct answer)
- Analyze
- Improve
Correct answer: Measure
The Measure phase is dedicated to collecting data and establishing the current baseline performance of the process before any improvements are made, providing a foundation for comparison.
Question 3: What does a p-value less than 0.05 indicate in hypothesis testing?
- The null hypothesis is proven true
- There is insufficient evidence to draw a conclusion
- The result is statistically significant and the null hypothesis is rejected (Correct answer)
- The sample size is too small
Correct answer: The result is statistically significant and the null hypothesis is rejected
A p-value below the significance level (typically 0.05) means the probability of observing the results by chance is very low, providing sufficient evidence to reject the null hypothesis.
Question 4: Which type of variation in a control chart is caused by identifiable, non-random sources such as equipment failure or operator error?
- Common cause variation
- Natural variation
- Special cause variation (Correct answer)
- Random variation
Correct answer: Special cause variation
Special cause variation (also called assignable cause variation) stems from specific, identifiable factors outside the normal process and is indicated by points beyond control limits or non-random patterns.
Question 5: What is the primary purpose of a Measurement System Analysis (MSA) in Six Sigma?
- To identify root causes of defects
- To evaluate the accuracy and reliability of the measurement system itself (Correct answer)
- To calculate the process sigma level
- To map the value stream of a process
Correct answer: To evaluate the accuracy and reliability of the measurement system itself
MSA (commonly conducted as a Gauge R&R study) assesses whether the measurement system introduces unacceptable variation, ensuring that data collected actually reflects true process performance rather than measurement error.
Question 6: In Six Sigma, what does the term 'sigma level' of a process primarily describe?
- The number of control charts used to monitor the process
- The number of process steps in the value stream
- How many standard deviations fit between the process mean and the nearest specification limit (Correct answer)
- The total cost of quality for the process
Correct answer: How many standard deviations fit between the process mean and the nearest specification limit
The sigma level measures process capability by indicating how many standard deviations fit between the mean and the closest specification limit; a higher sigma level means fewer defects and better performance.
Certified Six Sigma Black Belt Exam Certified Six Sigma Black Belt Basic 1
Which tool is used to prioritize potential causes of a problem by separating the 'vital few' from the 'trivial many'?