Question: A manufacturer of large appliances maintains a p chart for the production of washing machines. The machines may be rejected because of cosmetic or functional defectives. Based on sampling 30 machines each day for 50 consecutive days, the current estimate of p is .0855.
a. What are the control limits for a p chart? (Assume 3- limits.)
b. Suppose that the percentage of defective washing machines increases to 20 percent. What is the probability that this shift is detected on the first day after it occurs?
c. On average, how many days would be required to detect the shift?