ASQ Certified Six Sigma Black Belt (CSSBB) — Question 4

A ___________ is used primarily to track the stability of the average value of a metric of interest.

Answer options

• A. NP Chart
• B. Xbar-R Chart
• C. I-MR Chart
• D. C Chart

Correct answer: B

Explanation

The Xbar-R Chart is designed to track the average and range of a process, making it suitable for monitoring the stability of the mean value. The NP Chart is used for attribute data, the I-MR Chart is for individual measurements, and the C Chart is intended for counting defects, thus they do not focus on the average value of a metric.