Lean Six Sigma Black Belt Certification Statistical Process Control (SPC) 2

Question 1

A process has a Cpk of 0.85. What does this indicate?

Accepted Answer

The process is not capable of meeting specifications

Answer

A Cpk below 1.0 indicates the process is not capable of consistently meeting specification limits.

Question 2

Which Western Electric rule is violated when 2 out of 3 consecutive points fall beyond 2 sigma on the same side of the centerline?

Accepted Answer

Rule 2

Answer

Western Electric Rule 2 flags 2 out of 3 consecutive points beyond 2 sigma on the same side as a signal of special cause.

Question 3

What is the primary purpose of the CUSUM chart?

Accepted Answer

Detect small, sustained shifts in the mean over time

Answer

CUSUM (Cumulative Sum) charts are specifically designed to detect small, sustained process mean shifts that Shewhart charts may miss.

Question 4

In an np-chart, what does 'n' represent?

Accepted Answer

Constant subgroup size

Answer

In an np-chart, 'n' is the constant subgroup size; the chart plots the count of nonconforming items using a fixed sample size.

Question 5

Which measure describes the within-subgroup short-term variation used to estimate sigma in control chart calculations?

Accepted Answer

Average range (R-bar)

Answer

The average range (R-bar) captures within-subgroup variation and is used to estimate the short-term process standard deviation for control limit calculations.

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Practice Test

Lean Six Sigma Black Belt Certification Statistical Process Control (SPC) 2