In its Fuel Economy Guide for 2008 model vehicles, the Environmental Protection Agency gives data on 1152 vehicles. There are a number of outliers, mainly vehicles with very poor gas mileage. If we ignore the 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. 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?

%

How high must a 2008 vehicle's gas mileage be in order to fall in the top 20% of all vehicles? (The distribution omits a few high outliers, mainly hybrid gas-electric vehicles.)

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?

Gas mileage of the first quartile:
Gas mileage of the third quartile:

The quintiles of any distribution are the values with cumulative proportions 0.20, 0.40, 0.60, and 0.80. What are the quintiles of the distribution of gas mileage?

Gas mileage of 0.20 of the distribution:
Gas mileage of 0.40 of the distribution:
Gas mileage of 0.60 of the distribution:
Gas mileage of 0.80 of the distribution:

1.3.4 practice : modeling: solving linear equations in this assignment, you may work alone, with a partner, or in a small group. discuss the results of your work and/or any lingering questions with your teacher. your assignment: road trip you're taking a scenic road trip down ca-highway 1 from san jose, california, to los angeles. you plan to split the drive into two days, stopping for one night. choose one town to stop in, and find the driving distance for the second day. 1. circle the town you chose to stop in. (1 point) santa barbara: an image of palm trees san luis obispo: an image of a church 2. why did you choose this town? (1 point) 3.what do you know? .what do you want to find out? .what kind of answer do you expect? define the variable. 4. what is the variable x for this problem? (1 point) write the equation. 5. write an equation showing that the distance traveled on the first day plus the distance traveled on the second day is equal to 425 miles. (4 points: 2 points for each side of the equation) isolate the variable. 6. what inverse operation do you need to perform on both sides to isolate x in the equation? (2 points: 1 point for the correct number, 1 point for the correct operation) solve the equation. 7. solve the equation for x. interpret the answer in terms of the problem. (2 points: 1 point for the solution, 1 point for the interpretation) check your solution. 8. to confirm that your answer is correct, add the two days' distances. this should equal the total distance from san jose to los angeles. show your work as an equation. (3 points: 1 point for the setup, 2 points for the correct answer)