Lean Six Sigma Yellow Belt Certification The Control Phase 3 — Questions and Answers
Question 1: What is a 'response plan' in the context of a control chart?
- A document listing all process improvement ideas
- A predetermined set of actions to take when the process goes out of control (Correct answer)
- A schedule for recalibrating measurement equipment
- A list of stakeholders to notify about project completion
Correct answer: A predetermined set of actions to take when the process goes out of control
A response plan specifies exactly what actions operators should take when a control chart signals an out-of-control condition.
Question 2: Which of the following is a visual management tool commonly used to sustain Control phase improvements?
- Fishbone diagram
- 5S workplace organization (Correct answer)
- SIPOC diagram
- Affinity diagram
Correct answer: 5S workplace organization
5S (Sort, Set in Order, Shine, Standardize, Sustain) creates visual workplace organization that makes abnormalities immediately obvious.
Question 3: In statistical process control (SPC), control limits are typically set at:
- ±1 standard deviation from the mean
- ±2 standard deviations from the mean
- ±3 standard deviations from the mean (Correct answer)
- The upper and lower specification limits
Correct answer: ±3 standard deviations from the mean
Control limits are set at ±3 standard deviations (sigma) from the process mean, capturing 99.73% of natural variation.
Question 4: What is 'process entrenchment' and why is it a risk in the Control phase?
- A statistical test that confirms process stability
- The tendency for teams to over-control stable processes
- The gradual reversion to old work habits that erodes improvements (Correct answer)
- A method for embedding controls directly into software systems
Correct answer: The gradual reversion to old work habits that erodes improvements
Process entrenchment refers to employees reverting to old habits over time, which is why standardization and monitoring are critical.
Question 5: A Cpk value of 1.33 generally indicates that a process is:
- Incapable and producing a high defect rate
- Marginally capable and requires close monitoring
- Capable and meeting industry minimum requirements (Correct answer)
- So capable that monitoring can be discontinued
Correct answer: Capable and meeting industry minimum requirements
A Cpk of 1.33 is the widely accepted minimum threshold for a capable process, corresponding to approximately 64 DPMO.
Question 6: Standard Operating Procedures (SOPs) created during the Control phase should be:
- Written only by engineers and stored in a central database
- Written in technical language to ensure precision
- Written clearly enough for any trained operator to follow independently (Correct answer)
- Updated monthly regardless of whether the process has changed
Correct answer: Written clearly enough for any trained operator to follow independently
Effective SOPs are written at the appropriate literacy level so any qualified operator can execute the process consistently without interpretation.
Question 7: Which of the following is an example of an 'administrative control' used to sustain improvements?
- Installing a sensor that stops the machine when a defect is detected
- Redesigning the assembly jig to prevent incorrect part orientation
- Requiring a supervisor's signature to confirm a checklist was completed (Correct answer)
- Painting floor markings to designate storage zones
Correct answer: Requiring a supervisor's signature to confirm a checklist was completed
Administrative controls rely on human behavior (checklists, approvals, audits) rather than physical or engineering barriers.
Lean Six Sigma Yellow Belt Certification The Control Phase 3
What is a 'response plan' in the context of a control chart?