Control and Sustainment Methods Flashcards
7 cards from real Lean Six Sigma Yellow 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 and Sustainment Methods flashcards as text
On a control chart, what does it mean when a single data point falls beyond the Upper Control Limit (UCL)?
Answer: A special cause of variation is likely present
A point beyond the UCL is one of the Western Electric rules indicating a special cause of variation that requires investigation.
A control plan should be updated whenever:
Answer: A process change or improvement is implemented
Control plans must reflect the current process state, so any process change or improvement requires an update to keep the plan accurate.
Which type of control chart is best suited for monitoring the proportion of defective items in a process?
Answer: p-chart
A p-chart tracks the proportion (fraction) of nonconforming items and is used when sample sizes may vary.
What is the primary purpose of a response plan within a control plan?
Answer: To outline corrective actions when a process goes out of control
A response plan tells operators exactly what steps to take when control chart signals indicate the process is out of control.
In a control chart, the Lower Control Limit (LCL) is calculated as:
Answer: Mean minus 3 standard deviations
Control limits are set at ±3 standard deviations from the process mean, so the LCL = mean − 3σ.
Which of the following is a benefit of using Statistical Process Control (SPC) in the Control phase?
Answer: It detects shifts in process performance before defects are produced in large quantities
SPC enables early detection of process drift or shifts so corrective action can be taken before many defects occur.
What does 'common cause variation' on a control chart indicate?
Answer: The process is behaving normally and is in statistical control
Common cause variation is the natural, inherent variability of a stable process and does not require special investigation.