Wayne Merritt drives from Cleveland to Chicago frequently and has noticed that traffic and weather make a big difference in the time it takes to make the trip. As a result, he has a hard time planning activities around his arrival time. To better plan his business, Wayne wants to calculate his average driving time as well as a measure of how much an actual trip is likely to vary from that average. To do that, he clocked 10 trips with the following results:

Driving Time Number of trips

6 hrs, 0 min ................1

6 hrs, 15 min ................1

6 hrs, 30 min .................2

6 hrs, 45 min .................3

7 hrs, 0 min .................1

7 hrs, 30 min ................1

9 hrs, 20 min ................1

a. Calculate the mean, standard deviation, and coefficient of variation of Wayne’s driving time to Chicago.

b. Calculate the average variation in driving time. Compare the standard and average variations. Is the difference significant? Which is more meaningful to Wayne?