IASSC Certified Lean Six Sigma Black Belt (ICBB) — Question 96

If a process has subgroups for Variable data and the process runs for a long period of time, then the best pair of SPC Charts to use would be an Xbar and
_________.

Answer options

• A. NP Chart
• B. Individuals Chart
• C. R Chart
• D. C Chart

Correct answer: C

Explanation

The correct answer is C, R Chart, because it is used to monitor the variability within the subgroups when the process is stable over time. The NP Chart, Individuals Chart, and C Chart are not suitable for monitoring the variability of a process with subgroups, as they serve different purposes in statistical process control.