Vehicle Mileage Statistical Analysis
The Environmental Protection Agency (EPA) fuel economy estimates for automobile models tested recently predicted a mean = 24.8 miles per gallon and a standard deviation a = 6.2 miles per gallon for highway driving. Assume a normal distribution.
Use this information to answer questions #13 – #14.
(13) Use Table 4 (Standard Normal probability table), software, or the TI-83 to find the probability that a randomly selected automobile gets between 31 mpg and 37 mpg.
14) Find the gas mileage of the worst 2.5% of all cars. Transform a z-score into an x-value.