Repeat Exercise 8, using the S chart in place of the R chart. 10. A certain type of integrated circuit is connected to its frame by five wires. Thirty samples of five units each were taken, and the pull strength (in grams) of one wire on each unit was measured. The data are presented in Table E10 on page 513. The means are X = 9.81, R = 1.14, and s = 0.4647.

a. Compute the 3???? limits for the R chart. Is the variance out of control at any point? If so, delete the samples that are out of control and recompute X and R.

b. Compute the 3???? limits for the X chart. On the basis of the 3???? limits, is the process mean in control?

If not, at what point is it first detected to be out of control?

c. On the basis of the Western Electric rules, is the process mean in control? If not, when is it first detected to be out of control?