Five Samples of Size 4 Were Taken from a Process $\bar{x}$

Multiple Choice

Five samples of size 4 were taken from a process. A range chart was developed that had LCLR = 0 and UCLR = 2.50. Similarly, an average chart was developed with the average range from the five samples, with LCL $\bar{x}$ = 15.0 and LCL $\bar{x}$ = 24.0. The ranges for each of the five samples were 1.75, 2.42, 2.75, 2.04, and 2.80, respectively. The values of the sample average for each sample were 19.5, 22.3, 17.4, 20.1, and 18.9, respectively. What can you tell management from this analysis?

A) The process variability is out of control, and we cannot make a statement about the process average.
B) The process variability is out of control, but the process average is in control.
C) The process variability and the process average are out of control.
D) We cannot tell if the process variability or the process average is out of control.