A person investigating the relation between car weight and gas mileage reasons that because heavier cars tend to have bigger engines and because bigger engines weigh more, any relation between car weight and gas mileage may be “contaminated” by engine size. Use the data in the file 04Cars.sav (see previous problem) to assess the relation between gas mileage (use HiwayMPG) and car weight (Weight) controlling for (i.e., over and above) the influence of engine size (Engine) on gas mileage. As in exercise 1, omit the data of the hybrid vehicles (case numbers 69, 70, and 94) before performing the analysis.