a. In its Fuel Economy Guide for 2008 model vehicles, the Environmental Protection Agency of the USA gives data on 1152 vehicles. There are a number of outliers, mainly vehicles with very poor gas mileage. If we ignore outliers, however, the combined city and highway gas mileage of the other 1120 or so vehicles is approximately Normal with mean 18.7 miles per gallon (mpg) and standard deviation 4.3 mpg. i. The 2008 Chevrolet Malibu with a four-cylinder engine has combined gas mileage 25 mpg. What percent of all vehicles have worse gas mileage than the Malibu? ii. How high must a 2008 vehicle's gas mileage be in order to fall in the top 10 % of all vehicles?

b. The time (Y) it takes a professor to drive home each night is normally distributed with mean 15 minutes and standard deviation 2 minutes. Find the following probabilities. Draw a picture of the normal distribution and show (shade) the area that represents the probability you are calculating. i. P(Y > 25) = ii. P( 11 < Y < 19) = iii. P (Y < 18) =