LMC Quality Assurance & Improvement 3 — Questions and Answers
Question 1: In the DMAIC improvement cycle, during which phase are process capability studies and control charts most commonly established?
- Define
- Measure
- Analyze
- Control (Correct answer)
Correct answer: Control
The Control phase establishes monitoring systems like control charts to sustain improvements and detect future deviations.
Question 2: A supervisor implements a standard that requires operators to check part dimensions every 10 pieces. This practice is an example of:
- Pull system implementation
- In-process inspection (sampling control) (Correct answer)
- Value stream mapping
- Setup reduction
Correct answer: In-process inspection (sampling control)
Periodic in-process inspection using sampling helps detect shifts in quality early without inspecting every unit.
Question 3: Which Lean principle states that quality should be built into the product rather than inspected in at the end?
- Just-in-time
- Built-in quality (jidoka) (Correct answer)
- Heijunka
- Muda elimination
Correct answer: Built-in quality (jidoka)
Built-in quality (jidoka) holds that processes should be designed to detect and prevent defects, not rely on final inspection.
Question 4: A control chart shows several data points alternating consistently above and below the centerline. This pattern is most likely caused by:
- Natural process variation
- Operator rotation between two differently calibrated machines (Correct answer)
- A sudden machine breakdown
- Random sampling error
Correct answer: Operator rotation between two differently calibrated machines
A consistent alternating pattern on a control chart often signals systematic differences between two sources, such as operators or machines.
Question 5: When applying FMEA (Failure Mode and Effects Analysis) in Lean quality improvement, the Risk Priority Number (RPN) is calculated as:
- Severity + Occurrence + Detection
- Severity × Occurrence × Detection (Correct answer)
- Severity ÷ Detection × Occurrence
- Occurrence × Severity − Detection
Correct answer: Severity × Occurrence × Detection
RPN = Severity × Occurrence × Detection; higher RPN values identify failure modes that require priority corrective action.
Question 6: A Lean quality team is reviewing a process where the customer specification range is narrow but process variation is wide. The best immediate action is to:
- Widen the customer specification
- Perform root cause analysis to reduce process variation (Correct answer)
- Increase inspection frequency only
- Move to a batch production model
Correct answer: Perform root cause analysis to reduce process variation
When variation exceeds specification limits, root cause analysis and process improvement are required to reduce variation and improve capability.
Question 7: Which statement best describes the relationship between standardized work and quality improvement in Lean?
- Standardized work restricts quality improvement by limiting operator initiative
- Standardized work establishes the current best method, providing a stable baseline for improvement (Correct answer)
- Standardized work is only relevant to productivity, not quality
- Standardized work eliminates the need for control charts
Correct answer: Standardized work establishes the current best method, providing a stable baseline for improvement
Standardized work defines the best known method, ensuring consistency and providing a baseline from which improvements can be measured.
LMC Quality Assurance & Improvement 3
In the DMAIC improvement cycle, during which phase are process capability studies and control charts most commonly established?