EXAMPLE 1.15

How long are customer service center calls? We have data on the lengths of all 31,492 calls made to the customer service center of a small bank in a month. Table 1.2 displays the lengths of the first 80 calls.⁵

Take a look at the data in Table 1.2. In this data set, the cases are calls made to the bank’s call center. The variable recorded is the length of each call. The units are seconds. We see that the call lengths vary a great deal. The longest call lasted 2631 seconds, almost 44 minutes. More striking is that 8 of these 80 calls lasted less than 10 seconds.