1.

Computers in some vehicles calculate various quantities related to performance. One of these is the fuel efciency, or gas mileage, usually expressed as miles per gallon (mpg). To test how well these computers work, a driver decides to compare these measurements to his own recordings of the mpg by dividing the miles driven by the number of gallons at each ll up. The following data are the differences between the computer's and the driver's calculations for that random sample of 20 records. The driver wants to determine of these calculations are different. Assume the standard deviation of a difference to be o=3.0 mpg. \"maxim\"_ [mm-"mm\