2.21 Navigating through an airport can be quite chaotic.

You could instead choose to spend your waiting time at one of the airport lounges—hospitality areas where you can relax and enjoy food and beverages before you jet off. A random sample of 10 airport lounges are selected and the following entry fees are listed below (in euros):

15 30 25 32 40 18 22 28 25 35

a. Find the mean entry fee.

b. Calculate the standard deviation using Equation 2.13.

c. Calculate the standard deviation using Equation 2.14.

d. Calculate the standard deviation using Equation 2.15.

e. Find the coefficient of varaition.