. Miles per Gallon. In its Fuel Economy Guide for 2019 model vehicles, the Environmental Protection Agency gives data on 1259 vehicles. There are numbers of high outliers, mainly hybrid gas–electric vehicles. If we ignore the vehicles identified as outliers, however, the combined city and highway gas mileage of the other 1231 vehicles is approximately Normal with mean 22.8 miles per gallon (mpg) and standard deviation 4.8 mpg.
a. The 2019 Volkswagen Beetle with a four-cylinder 2.0-L engine and automatic transmission has combined gas mileage of 29 mpg. What percentage of all vehicles have better gas mileage than the Beetle?
b. How high must a 2019 vehicle’s gas mileage be to fall in the top 15% of all vehicles?
c The quartiles of any distribution are the values with cumulative proportions 0.25 and 0.75. They span the middle half of the distribution. What are the quartiles of the distribution of gas mileage?
