Suppose That $\overline { \mathrm { X } }$ And R Charts Based on Subgroups of Size 4 Are

Multiple Choice

Suppose that $\overline { \mathrm { X } }$
And R charts based on subgroups of size 4 are being used to monitor the tire diameter.The $\overline { \mathrm { X } }$
And R charts are found to be in statistical control,with $\overline { \overline { X } } = 50.25 , \bar { R } = .8$

Inches.A histogram of the tire diameter measurements indicates that these measurements are approximately normally distributed.Find the sigma level capability of the process.

A) 1.93
B) 3.22
C) 0.64
D) 0.22