Lean Six Sigma Green Belt Certification Lean Principles and Waste 3 — Questions and Answers
Question 1: Which waste type occurs when a finished product must be reworked because it failed an inspection?
- Waiting
- Over-processing
- Defects (Correct answer)
- Overproduction
Correct answer: Defects
Defects waste includes any rework, scrap, or correction required because a product did not meet quality standards the first time.
Question 2: A Lean practitioner maps a process and finds that 85% of lead time is spent waiting for approval signatures. Which improvement should be prioritized?
- Reduce batch sizes
- Eliminate the waiting waste by streamlining approvals (Correct answer)
- Implement 5S in the office
- Add more inspectors
Correct answer: Eliminate the waiting waste by streamlining approvals
Waiting waste accounts for 85% of lead time here, so streamlining or automating approval steps will deliver the greatest cycle time reduction.
Question 3: In Lean, which term describes the rate at which products must be completed to meet customer demand?
- Cycle time
- Takt time (Correct answer)
- Lead time
- Throughput time
Correct answer: Takt time
Takt time is calculated as available production time divided by customer demand rate, setting the pace for production to avoid over- or under-production.
Question 4: Which of the 5 Lean principles focuses on ensuring that each step in the process flows into the next without interruption or delay?
- Define Value
- Map the Value Stream
- Create Flow (Correct answer)
- Establish Pull
Correct answer: Create Flow
The 'Create Flow' principle aims to eliminate interruptions, queues, and batches so work moves continuously through the value stream.
Question 5: A hospital moves patient records from nursing to billing through three separate departments before processing. This is an example of which waste?
- Motion
- Transportation (Correct answer)
- Inventory
- Waiting
Correct answer: Transportation
Transportation waste involves the unnecessary movement of materials, information, or products — in this case, patient records passed through multiple departments.
Question 6: Which Lean tool is specifically designed to provide a visual representation of all value-added and non-value-added steps in a process?
- Control chart
- Value stream map (Correct answer)
- Fishbone diagram
- SIPOC diagram
Correct answer: Value stream map
A value stream map visually depicts every process step, information flow, and timeline, highlighting value-added vs. non-value-added activities.
Question 7: Which type of non-value-added activity is considered 'necessary' in Lean and should be minimized rather than immediately eliminated?
- Rework due to defects
- Regulatory compliance inspections (Correct answer)
- Waiting for a machine setup
- Transporting goods between plants
Correct answer: Regulatory compliance inspections
Regulatory compliance inspections are non-value-added but necessary; they cannot be eliminated without violating requirements, so they should be minimized instead.
Lean Six Sigma Green Belt Certification Lean Principles and Waste 3
Which waste type occurs when a finished product must be reworked because it failed an inspection?