Fifteen Samples of Size 10 Are Taken from a Stable

Multiple Choice

Fifteen samples of size 10 are taken from a stable process. The average of the sample means is 32.8, and the average range of the samples is 1.5. Use the information contained in the chart below (Table 13s.1) :

-The UCL for the three sigma X bar chart for the process is approximately (for a sample size of 10, A₂ = 0.308) :

A) 32.34
B) 33.26
C) 32.80
D) 32.28
E) 32.64