6.44 Fuel efficiency.
Computers in some vehicles calculate various quantities related to performance. One of these is the fuel efficiency, or gas mileage, usually expressed as miles per gallon (mpg). For one vehicle equipped in this way, the car was set to 60 miles per hour by cruise control, and the mpg were recorded at random times.13 Here are the mpg values from the experiment:
mileage
37.2 | 21.0 | 17.4 | 24.9 | 27.0 | 36.9 | 38.8 | 35.3 | 32.3 | 23.9 |
19.0 | 26.1 | 25.8 | 41.4 | 34.4 | 32.5 | 25.3 | 26.5 | 28.2 | 22.1 |
Suppose that the standard deviation of the population of mpg readings of this vehicle is known to be .