2. A Quality Analyst wants to construct a control chart for determining whether the four machines are under control or not, by checking the total defectives in the output. Accordingly, he inspected 1,000 units of output from each machine in random samples, with the following results: Machine # of defectives 1 23 2 15 3 29 4 13 Find: a. The average of sample proportions of defectives? b. The standard deviation of the sampling distributionc. The control chart upper and

c. The control chart upper and lower control limits that describe 95 percent of the chance variation in the process when the process is in control? d. And which machine(s), if any, appear(s) to be out-of-control for process proportion of defectives?