Call centers today play an important role in managing day-to-day business communications 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 a financial services call center: At the 0.05 level of significance, is there evidence that the population mean time to answer calls is less than 20 seconds