DMAIC: Improve and Control Flashcards
7 cards from real Lean Six Sigma Green Belt Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 DMAIC: Improve and Control flashcards as text
Which metric best quantifies the long-term process capability when the process mean is not centered between specification limits?
Answer: Ppk
Ppk measures long-term process performance accounting for both the actual process spread and how far the mean is from the nearest specification limit.
A team wants to reduce setup time on a manufacturing line. Which Lean technique specifically targets the reduction of changeover time?
Answer: SMED (Single-Minute Exchange of Die)
SMED is a systematic approach to reduce changeover time by converting internal setup steps (done while the machine is stopped) to external steps (done while it runs).
What is the key difference between corrective action and preventive action in a control plan?
Answer: Corrective action responds to an out-of-control event; preventive action eliminates potential causes before they occur
Corrective action is reactive, taken after a defect or special cause is detected, while preventive action is proactive, removing the root cause of a potential failure before it materializes.
A process has a Cpk of 0.85. What does this indicate?
Answer: The process is producing defects and is not fully capable
A Cpk below 1.0 indicates the process is producing output outside the specification limits and is not yet capable of meeting customer requirements.
During an experiment, a team notices that temperature and pressure consistently change together across runs. This is an example of which experimental design problem?
Answer: Confounding due to lurking variable
When two variables move together unintentionally across experimental runs, their effects become entangled, making it impossible to attribute results to either factor independently.
A team uses an EWMA (Exponentially Weighted Moving Average) control chart instead of a Shewhart X-bar chart. What is the primary advantage?
Answer: EWMA is more sensitive to small, sustained process shifts
EWMA gives more weight to recent observations and accumulates information over time, making it better at detecting small persistent shifts that a Shewhart chart might miss.
At project closure, the Green Belt should confirm financial benefits with which function before reporting them to leadership?
Answer: The finance or accounting department
Financial benefits must be validated by Finance or Accounting to ensure they are recognized on the income statement or balance sheet and reported accurately to leadership.