Lean Six Sigma Yellow Belt Certification The Control Phase 5 — Questions and Answers
Question 1: An operator notices 8 consecutive data points on the same side of the centerline in a control chart. This is called:
- A normal random pattern requiring no action
- A run rule violation indicating a potential process shift (Correct answer)
- Evidence that the control limits are set incorrectly
- Proof that the measurement system is biased
Correct answer: A run rule violation indicating a potential process shift
Eight consecutive points on one side of the centerline is a run rule violation signaling a likely process shift, even if no points are outside control limits.
Question 2: How does a control plan differ from a project charter?
- A control plan defines the project scope; a charter defines monitoring activities
- A control plan is a living document used post-project; a charter initiates the project (Correct answer)
- A control plan is created in the Define phase; a charter is created in the Control phase
- There is no meaningful difference between the two documents
Correct answer: A control plan is a living document used post-project; a charter initiates the project
The project charter launches the DMAIC project, while the control plan is created at the end to govern ongoing process management after project closure.
Question 3: Which of the following best illustrates 'visual management' in a sustained process?
- A statistical report emailed to managers each week
- Color-coded floor tape marking where materials should be stored (Correct answer)
- A database of all historical defect records
- A control chart stored in the quality manager's office
Correct answer: Color-coded floor tape marking where materials should be stored
Visual management makes the correct condition immediately obvious to anyone in the work area without needing to consult a report.
Question 4: In the Control phase, 'piloting' a solution before full deployment helps to:
- Satisfy the Define phase gate review requirements
- Reduce risk by testing the control mechanism on a small scale first (Correct answer)
- Calculate the return on investment before project closure
- Identify additional root causes that were missed in the Analyze phase
Correct answer: Reduce risk by testing the control mechanism on a small scale first
Piloting on a small scale confirms that control mechanisms work as intended before committing to full-scale implementation.
Question 5: What is the significance of a Cpk value less than 1.0?
- The process is highly capable and exceeds customer expectations
- The process is centered but variation is too wide for the specification
- The process is incapable and is producing output outside specification limits (Correct answer)
- The process requires no further monitoring or improvement
Correct answer: The process is incapable and is producing output outside specification limits
A Cpk below 1.0 means the process is producing defects outside the specification limits and is considered incapable.
Question 6: Which of the following is the BEST reason to involve the process owner in the Control phase from the beginning?
- To reduce the project team's workload during data collection
- To ensure they understand and are committed to sustaining the improvements (Correct answer)
- To provide statistical expertise for building control charts
- To approve the financial benefits claimed in the project charter
Correct answer: To ensure they understand and are committed to sustaining the improvements
Early involvement builds the process owner's understanding and ownership, making them more likely to sustain improvements after project closure.
Question 7: A team implements a new inspection step at the end of a process to catch defects before they reach the customer. This is an example of:
- Prevention-based control
- Detection-based control (Correct answer)
- Process capability improvement
- Mistake-proofing (poka-yoke)
Correct answer: Detection-based control
An inspection step detects defects after they occur rather than preventing them, making it a detection-based control.
Lean Six Sigma Yellow Belt Certification The Control Phase 5
An operator notices 8 consecutive data points on the same side of the centerline in a control chart.
This is called: