3. Refer to Exercise 10 in Section 10.2.

a. Delete any samples necessary to bring the process variation under control. (You did this already if you did Exercise 10 in Section 10.2.)

b. Use R to estimate σX (σX is the difference between X and the 1σ control limit on an X chart).

c. Construct a CUSUM chart, using X for the target mean µ, and the estimate of σX found in part

(b) for the standard deviation. Use the values k = 0.5 and h = 4.

d. Is the process mean in control? If not, when is it first detected to be out of control?

e. Construct an X chart, and use the Western Electric rules to determine whether the process mean is in control. (You did this already if you did Exercise 10 in Section 10.2.) Do the Western Electric rules give the same results as the CUSUM chart? If not, how are they different?