Question 12.46

12.46 Call center.

A large nationwide retail chain keeps track of a variety of statistics on its service call center. One of those statistics is the length of time a customer has to wait before talking to a representative. Based on call center research and general experience, the retail chain has determined that it is unacceptable for any customer to be on hold for more than 90 seconds. To monitor the performance of the call center, a random sample of 200 calls per shift (three shifts per day) is obtained. Here are the number of unacceptable calls in each sample for 15 consecutive shifts over the course of one business week:

callc

Shift Shift 1 Shift 2 Shift 3 Shift 1 Shift 2 Shift 3
Unacceptable 6 17 6 9 16 10
Shift Shift 1 Shift 2 Shift 3 Shift 1 Shift 2 Shift 3
Unacceptable 8 14 5 6 16 6
Shift Shift 1 Shift 2 Shift 3
Unacceptable 9 14 7
  1. What is for the call center process?
  2. What are the center line and control limits for a chart for plotting proportions of unacceptable calls?
  3. Label the data points on the chart by the shift. What do you observe that the chart limits failed to pick up?