Control Phase and Sustainment 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 Control Phase and Sustainment flashcards as text
A Green Belt notices a control chart with a run of 8 consecutive points above the centerline. What action should be taken?
Answer: Investigate for a special cause even though limits are not breached
Eight consecutive points on one side of the centerline is a non-random pattern (Western Electric Rule) indicating a special cause that requires investigation regardless of control limit violations.
Which document is MOST effective for ensuring operators consistently follow a newly optimized process?
Answer: Standard Operating Procedure (SOP)
A Standard Operating Procedure (SOP) provides step-by-step instructions that standardize how operators perform tasks, directly supporting process sustainment.
During a control plan review, the team finds that a CTQ characteristic has a Cpk of 0.85. What does this indicate?
Answer: The process is not capable and is producing defects
A Cpk below 1.0 indicates the process is not capable of consistently meeting specifications and is likely producing defects or out-of-spec output.
What is the PRIMARY purpose of a response plan within a control plan?
Answer: To describe corrective actions when a process goes out of control
A response plan specifies the corrective actions operators and supervisors should take when a control chart signals an out-of-control condition.
A team implementing statistical process control (SPC) should establish control limits using data from:
Answer: A period when the process was known to be stable and in control
Control limits must be calculated from historical data collected when the process was stable, so they reflect natural process variation rather than specification requirements.
Which type of control chart is BEST suited for monitoring the proportion of defective items in a process with varying subgroup sizes?
Answer: p chart
The p chart monitors the proportion of defectives and automatically adjusts control limits for varying subgroup sizes, making it appropriate when sample sizes differ.
Visual management tools in a control system serve to:
Answer: Make process status immediately apparent to anyone on the floor
Visual management (e.g., color-coded gauges, shadow boards, andon lights) makes the current process state instantly visible so that abnormalities are noticed quickly by everyone.