Solve the following problem:
Q: The Great North Woods Clothing Company is a mail-order company that processes thousands of mail and telephone orders each week. They have a customer service number to handle customer order problems, inquiries, and complaints. The company wants to monitor the number of customer calls that can be classified as complaints. The total number of complaint calls the customer service department has received for each of the last 30 weekdays are shown as follows:
Day Calls Day Calls
1 27 16 19
2 15 17 12
3 38 18 17
4 41 19 18
5 19 20 26
6 23 21 31
7 21 22 14
8 16 23 18
9 33 24 26
10 35 25 27
11 26 26 35
12 42 27 20
13 40 28 12
14 35 29 16
15 25 30 15?
a. Construct a c-chart for this process with 3 control limits and indicate if the process was out of control at any time.
b. What nonrandom (i.e., assignable) causes might result in the process being out of control?