Chapter 9, Problem 75PS

Call centers today play an important role in managing day-to-day business communication with customers. It’s important, therefore, to monitor a comprehensive set of metrics, which can help businesses understand the overall performance of a call center. One key metric for measuring overall call center performance is service level which is defined as the percentage of calls answered by a human agent within a specified number of seconds. The file ServiceLevel contains the following data for time, in seconds, to answer 50 incoming calls to financial service call center:

a. At the 0.05 level of significance, is there evidence that the population mean time to answer calls is less than 20 seconds?

b. What assumption about the population distribution is needed is order to conduct the t test in (a)?

c. Construct a histogram, boxplot, or normal probability plot to evaluate the assumption made in (b).

d. Do you think that the assumption needed in order to conduct the t test in (a) is valid? Explain.