GAT Quality Assurance and Improvement 3 — Questions and Answers
Question 1: In Six Sigma, what does a process operating at 'six sigma' level mean in practice?
- Zero defects are produced
- No more than 3.4 defects per million opportunities (Correct answer)
- All processes are automated
- Specifications are set at ±6 standard deviations
Correct answer: No more than 3.4 defects per million opportunities
Six Sigma quality means producing no more than 3.4 defects per million opportunities, accounting for a 1.5-sigma process shift.
Question 2: Which phase of the DMAIC framework focuses on identifying the root causes of defects?
- Define
- Measure
- Analyze (Correct answer)
- Improve
Correct answer: Analyze
The Analyze phase uses statistical and graphical tools to identify root causes of the problem identified earlier.
Question 3: A quality team wants to verify whether a process improvement actually reduced defect rates. Which statistical tool is most appropriate?
- Cause-and-effect diagram
- Hypothesis testing (Correct answer)
- Flow chart
- SIPOC diagram
Correct answer: Hypothesis testing
Hypothesis testing determines whether observed differences in defect rates are statistically significant or due to chance.
Question 4: What is the primary purpose of a SIPOC diagram in quality improvement projects?
- To map control limits for key process metrics
- To provide a high-level overview of a process and its stakeholders (Correct answer)
- To rank defect causes by frequency
- To track daily defect counts
Correct answer: To provide a high-level overview of a process and its stakeholders
SIPOC (Suppliers, Inputs, Process, Outputs, Customers) gives a broad process view at the start of an improvement project.
Question 5: Which of the following is an example of an 'internal failure cost' in quality management?
- Customer warranty claims
- Product recall costs
- Rework performed before product ships (Correct answer)
- Lost customer goodwill
Correct answer: Rework performed before product ships
Internal failure costs occur when defects are found and corrected before the product reaches the customer, such as rework.
Question 6: A company compares its quality metrics against those of the best-performing companies in its industry. This practice is called:
- Root cause analysis
- Benchmarking (Correct answer)
- Gap analysis
- Process auditing
Correct answer: Benchmarking
Benchmarking involves comparing processes, products, or metrics to industry leaders to identify improvement opportunities.
Question 7: Which type of variation in a process is caused by factors that are always present and inherent to the process design?
- Special cause variation
- Assignable cause variation
- Common cause variation (Correct answer)
- Sporadic variation
Correct answer: Common cause variation
Common cause variation is the natural, inherent variability in a stable process and can only be reduced by redesigning the process.
GAT Quality Assurance and Improvement 3
In Six Sigma, what does a process operating at 'six sigma' level mean in practice?