The data in the following table, part of a set of data collected by Ledolter and Hogg, provide the number of miles per gallon (mpg) for city and highway driving of 2007 midsize-model cars, as well as the curb weight of the cars:

(a) Find the least squares regression line for highway mpg (y) and city mpg (x).
(b) Plot the points and the least squares regression line on the same graph.
(c) Repeat parts (a) and (b) for the regression of highway mpg (y) on curb weight (x).

mpg mpg Curb City Hwy Weight Type Ford Fusion V6 SE Chevrolet Sebring Sedan Base Toyota Camry Solara SE Honda Accord Sedan Audi A6 3.2 BMW 5-series 525i Sedan Chrysler PT Cruiser Base Mercedes E-Class E350 Sedan Volkswagen Passat Sedan 2.0T Nissan Altima 2.5 Kia Optima LX 20 24 24 34 3240 20 29 21 29 3825 20 29 22 29 3076 19 23 26 24 28 3230 32 3287 3344 3450 263740 32 3305 35 34 3055 3142