Exhibit 13 -Refer to Exhibit 13

Essay

Exhibit 13.3
The following questions refer to the information below.
A company has recorded the following customer inter-arrival times and service times for 10 customers at one of its single teller service lines.Assume the data are exponentially distributed and the 10 data points represent a reasonable sample.
All time in minutes
$$\begin{array} { r r r } \text { Customer } & \text { Inter-arrival } & \text { Service } \\\hline 1 & 11.08 & 2.20 \\2 & 2.50 & 2.50 \\3 & 6.00 & 1.10 \\4 & 5.75 & 14.50 \\5 & 8.50 & 2.00 \\6 & 4.15 & 2.70 \\7 & 15.50 & 5.00 \\8 & 13.00 & 8.50 \\9 & 10.50 & 5.00 \\10 & 6.00 & 1.50\end{array}$$
-Refer to Exhibit 13.3.What is the average time a customer spends in the service line?