An $\bar { x }$ Chart Is Being Developed Using 15 Samples of Size 9

Multiple Choice

An $\bar { x }$ chart is being developed using 15 samples of size 9 each.The average of 15 sample means is 6.20.The average of the 15 ranges is 0.30.The upper control limit is _______________.

A) 6.301
B) 6.267
C) 6.133
D) 6.099
E) 6.312