Lean Six Sigma Yellow Belt Certification Control and Sustainment Methods 2

Question 1

On a control chart, what does it mean when a single data point falls beyond the Upper Control Limit (UCL)?

Accepted Answer

A special cause of variation is likely present

Answer

A point beyond the UCL is one of the Western Electric rules indicating a special cause of variation that requires investigation.

Question 2

A control plan should be updated whenever:

Accepted Answer

A process change or improvement is implemented

Answer

Control plans must reflect the current process state, so any process change or improvement requires an update to keep the plan accurate.

Question 3

Which type of control chart is best suited for monitoring the proportion of defective items in a process?

Accepted Answer

p-chart

Answer

A p-chart tracks the proportion (fraction) of nonconforming items and is used when sample sizes may vary.

Question 4

What is the primary purpose of a response plan within a control plan?

Accepted Answer

To outline corrective actions when a process goes out of control

Answer

A response plan tells operators exactly what steps to take when control chart signals indicate the process is out of control.

Question 5

In a control chart, the Lower Control Limit (LCL) is calculated as:

Accepted Answer

Mean minus 3 standard deviations

Answer

Control limits are set at ±3 standard deviations from the process mean, so the LCL = mean − 3σ.

Lean Six Sigma Yellow Belt Certification Practice Test