The U.S. Department of Energy's Fuel Economy Guide provides fuel efficiency data for cars and trucks (U.S. Department of Energy website, February 22, XXXXXXXXXXA portion of the data for 311 compact,...

The U.S. Department of Energy's Fuel Economy Guide provides fuel efficiency data for cars and trucks (U.S. Department of Energy website, February 22, 2008). A portion of the data for 311 compact, midsize, and large cars follows. The column labeled Class identifies the size of the car; Compact, Midsize, or Large. The column labeled Displacement shows the engine's displacement in liters. The column labeled Fuel Type shows whether the car uses premium (P) or regular (R) fuel, and the column labeled HwyMPG shows the fuel efficiency rating for highway driving in terms of miles per gallon. The complete data set is contained in the file namedFuelData.

(a)	Develop an estimated regression equation that can be used to predict the fuel efficiency for highway driving, given the engine's displacement.
Letxrepresent the engine's displacement.
If required, round your answers to four decimal places. For subtractive or negative numbers use a minus sign even if there is a + sign before the blank. (Example: -300)
=+x
Is there a relationship between HwyMPG and displacement at the 0.05 level of significance?
How much of the variation in the sample values of HwyMPG does this estimated regression equation explain?
If required, round your answer to two decimal places.
%
(b)	Create a scatter chart in Excel with HwyMPG on they-axis and displacement on thex-axis for which the points representing compact, midsize, and large automobiles are shown in different shapes and or colors.

(c)	Consider the addition of the dummy variables ClassMidsize and ClassLarge to the simple linear regression model in part (a). The value of ClassMidsize is 1 if the car is a midsize car and 0 otherwise; the value of ClassLarge is 1 if the car is a large car and 0 otherwise. Thus, for a compact car, the value of ClassMidsize and the value of ClassLarge are both 0. Develop the estimated regression equation that can be used to predict the fuel efficiency for highway driving, given the engine's displacement and the dummy variables ClassMidsize and ClassLarge.
Letx 1represent engine's displacement.
Letx 2represent variable ClassMidsize.
Letx 3represent variable ClassLarge.
If required, round your answers to four decimal places. For subtractive or negative numbers use a minus sign even if there is a + sign before the blank. (Example: -300)
=+x 1+x 2+x 3
How much of the variation in the sample values of HwyMPG does this estimated regression equation explain?
If required, round your answer to two decimal places.
% (e) Consider the addition of the dummy variable FuelPremium, where the value of FuelPremium is 1 if the car uses premium fuel and 0 if the car uses regular fuel. Develop the estimated regression equation that can be used to predict the fuel efficiency for highway driving, given the engine's displacement, the dummy variables ClassMidsize and ClassLarge, and the dummy variable FuelPremium. Letx 1represents engine's displacement. Letx 2represents variable ClassMidsize. Letx 3represents variable ClassLarge. Letx 4represents variable FuelPremium. If required, round your answers to four decimal places. For subtractive or negative numbers use a minus sign even if there is a + sign before the blank. (Example: -300) =+x 1+x 2+x 3+x 4 How much of the variation in the sample values of HwyMPG does this estimated regression equation explain? If required, round your answer to two decimal places. %