Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt Lean Principles and Waste 1 — Questions and Answers
Question 1: An assembly line worker must stop production for 20 minutes each shift while waiting for a parts delivery from an upstream supplier. Which of the 8 Lean wastes does this scenario most directly illustrate?
- Transportation
- Inventory
- Waiting (Correct answer)
- Motion
Correct answer: Waiting
Waiting waste occurs whenever people, machines, or materials are idle between process steps. The worker is not adding any value during those 20 minutes, making this a textbook example of waiting waste.
Question 2: Which of the following activities is considered value-added in a Lean process?
- Inspecting a finished product for defects before shipment
- Moving raw materials between two storage warehouses
- Machining a component to customer-specified dimensions (Correct answer)
- Storing completed assemblies while awaiting a purchase order
Correct answer: Machining a component to customer-specified dimensions
A value-added activity must (1) physically transform the product or service, (2) be done correctly the first time, and (3) be something the customer is willing to pay for. Only machining to customer specifications satisfies all three criteria.
Question 3: A quality team applies three coats of paint to a product when the customer specification requires only one coat for adequate protection. This is an example of which Lean waste?
- Defects
- Overproduction
- Overprocessing (Correct answer)
- Inventory
Correct answer: Overprocessing
Overprocessing waste occurs when more effort, precision, or quality is applied than the customer actually requires. The extra paint coats consume resources without adding customer-recognized value.
Question 4: A logistics company employs data analysts in manual sorting roles, never utilizing their statistical expertise. Which of the 8 Lean wastes does this represent?
- Motion
- Transportation
- Waiting
- Non-utilized talent (Correct answer)
Correct answer: Non-utilized talent
Non-utilized talent (also called Skills waste) occurs when employees' knowledge, creativity, or specialized skills are not leveraged. It was added as the 8th waste when Lean expanded beyond the original 7 identified by Toyota.
Question 5: A facility operates 8 hours per day with 30 minutes of scheduled breaks. Customer demand is 300 units per day. What is the takt time?
- 1.0 minute per unit
- 1.5 minutes per unit (Correct answer)
- 1.6 minutes per unit
- 2.0 minutes per unit
Correct answer: 1.5 minutes per unit
Takt time = Available production time ÷ Customer demand. Available time = (8 × 60) − 30 = 450 minutes. Takt time = 450 ÷ 300 = 1.5 minutes per unit. This is the pace at which production must flow to meet demand.
Question 6: A retail distributor maintains 90 days of safety stock on hand at all times to guard against stockouts. A Lean practitioner would most likely flag this as which type of waste?
- Defects
- Waiting
- Inventory (Correct answer)
- Overproduction
Correct answer: Inventory
Excess inventory ties up capital, requires storage space, risks obsolescence or damage, and — critically — hides underlying process problems such as unreliable suppliers or poor demand forecasting that should be addressed directly.
Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt Lean Principles and Waste 1
An assembly line worker must stop production for 20 minutes each shift while waiting for a parts delivery from an upstream supplier.
Which of the 8 Lean wastes does this scenario most directly illustrate?