The order-entry, order-processing call center for PS Industries is concerned about the amounts of time that customers must wait before their calls are handled. A quality improvement consultant suggests that it monitor call-wait times using control charts. Using call center statistics maintained by the company’s database system, the consultant randomly selects four calls every hour for 30 different hours and examines the wait time, in seconds, for each call. This information is contained in the file PS Industries.
Use the sample data to construct the appropriate control chart(s). Does the process appear to be in statistical control? What other information concerning the call center’s process should the consultant be aware of?