Certified Six Sigma Black Belt Exam Lean Enterprise Concepts 3 — Questions and Answers
Question 1: A lean team calculates that takt time is 60 seconds but cycle time at a bottleneck station is 80 seconds. What is the correct lean response?
- Add a second shift to meet demand
- Reduce cycle time at the bottleneck station through waste elimination or additional resources (Correct answer)
- Increase takt time by reducing customer demand targets
- Move inventory to a supermarket upstream of the bottleneck
Correct answer: Reduce cycle time at the bottleneck station through waste elimination or additional resources
When cycle time exceeds takt time, the process cannot meet customer demand, so waste elimination or resource addition at the constraint is required.
Question 2: In lean, 'mura' refers to:
- Physical waste or non-value-added activities
- Overburdening of people or equipment beyond their capacity
- Unevenness or variability in workflow and demand (Correct answer)
- Defects that escape to the customer
Correct answer: Unevenness or variability in workflow and demand
Mura (unevenness) is one of the three Ms in lean and represents inconsistency or variability in workload that generates the other two Ms.
Question 3: Which lean tool is specifically designed to balance workload evenly across operators in a work cell?
- Spaghetti diagram
- Operator balance chart (yamazumi chart) (Correct answer)
- SIPOC diagram
- Affinity diagram
Correct answer: Operator balance chart (yamazumi chart)
An operator balance chart (yamazumi) visually displays each operator's cycle time versus takt time, revealing imbalances and opportunities to rebalance tasks.
Question 4: A lean practitioner maps material and information flow to identify sources of waste and plan improvement. This mapping tool is called:
- Process flow diagram
- Value stream map (VSM) (Correct answer)
- Control chart
- Fishbone diagram
Correct answer: Value stream map (VSM)
Value stream mapping captures the current state of material and information flow, calculates key metrics, and serves as the basis for designing a future state.
Question 5: Standard work in lean is best described as:
- A rigid manufacturing specification that cannot be changed
- The current best-known method documented and consistently applied while improvement continues (Correct answer)
- ISO 9001-compliant work instructions for quality audits
- A control chart with upper and lower specification limits
Correct answer: The current best-known method documented and consistently applied while improvement continues
Standard work documents the current best method (sequence, timing, WIP) to ensure consistency and serve as the baseline for kaizen improvement.
Question 6: Which type of kanban system uses an empty container as the replenishment signal?
- Two-bin system (Correct answer)
- Electronic kanban (e-kanban)
- Single-card kanban
- Production leveling kanban
Correct answer: Two-bin system
In a two-bin system, the empty bin itself is the visual signal to replenish from a second bin or from the supplier/upstream process.
Question 7: When a lean team conducts a 'gemba walk,' the primary purpose is to:
- Audit compliance with ISO documentation requirements
- Observe actual work conditions at the place where value is created to identify problems and opportunities (Correct answer)
- Conduct employee performance reviews at their workstations
- Verify that 5S audit scores are maintained above target
Correct answer: Observe actual work conditions at the place where value is created to identify problems and opportunities
Gemba (the real place) walks involve leaders going to where work happens to observe, ask questions, and understand actual versus assumed conditions.
Certified Six Sigma Black Belt Exam Lean Enterprise Concepts 3
A lean team calculates that takt time is 60 seconds but cycle time at a bottleneck station is 80 seconds.
What is the correct lean response?