. Consider a 7 control chart for monitor- ing p=10 quality characteristics. Suppose that the subgroup size...

. Consider a 7ª control chart for monitor-

ing p=10 quality characteristics.

Suppose that the subgroup size is n = 3 and there are 25 preliminary samples available to estimate the sample covari-

ance matrix.

(a) Find the phase II control limits assuming that o = 0.005.

(b) Compare the control limits from part

(a) to the chi-square control limit. What is the magnitude of the difference in the two control limits?

(c) How many preliminary samples would have to be taken to ensure that the chi-square control limit is within 1% of the exact phase II con-
trol limit?