CPT Quality Assurance & Process Optimization 2 — Questions and Answers
Question 1: Which tool is used to identify which defects occur most frequently by ranking causes from highest to lowest frequency?
- Fishbone diagram
- Pareto chart (Correct answer)
- Control chart
- Scatter diagram
Correct answer: Pareto chart
A Pareto chart ranks defect causes by frequency, helping teams focus on the vital few problems that cause most issues.
Question 2: A process technician notices that consecutive data points on a control chart are all trending upward. This pattern is called a:
- Random variation
- Run (Correct answer)
- Common cause
- Specification limit breach
Correct answer: Run
A run is a sequence of consecutive points on the same side of or trending in one direction on a control chart, signaling a non-random pattern.
Question 3: PDCA stands for Plan, Do, Check, Act. Which phase involves comparing actual results against expected outcomes?
- Plan
- Do
- Check (Correct answer)
- Act
Correct answer: Check
The Check phase of PDCA compares measured results to the original goals to evaluate whether the change achieved the desired effect.
Question 4: Which type of process variation is inherent to the system and cannot be eliminated without changing the process itself?
- Assignable cause variation
- Special cause variation
- Common cause variation (Correct answer)
- Intermittent variation
Correct answer: Common cause variation
Common cause variation is natural, random variation built into the process design and requires systemic changes to reduce.
Question 5: A Cp value of 1.33 indicates that a process:
- Is barely capable of meeting specifications
- Is marginally incapable
- Has adequate capability with margin (Correct answer)
- Has no relationship to specification limits
Correct answer: Has adequate capability with margin
A Cp of 1.33 means the process spread fits within specification limits with a comfortable margin, indicating good capability.
Question 6: In a Six Sigma DMAIC project, during which phase are root causes of defects statistically validated?
- Define
- Measure
- Analyze (Correct answer)
- Improve
Correct answer: Analyze
The Analyze phase uses statistical tools to identify and confirm the root causes contributing to process defects.
Question 7: Which mistake-proofing method physically prevents an error from occurring rather than detecting it after the fact?
- Warning poka-yoke
- Control poka-yoke (Correct answer)
- Detection poka-yoke
- Audit poka-yoke
Correct answer: Control poka-yoke
A control poka-yoke stops the process or prevents the defect from occurring, while a warning poka-yoke only alerts the operator.
CPT Quality Assurance & Process Optimization 2
Which tool is used to identify which defects occur most frequently by ranking causes from highest to lowest frequency?