auto.rds dataset and variable description slide discussed in class. In addition to other variables, the dataset contains price, mpg, weight, length, and foreign (foreign vs. domestic) for 74 cars. Suppose the variables listed above are the only determinants of an auto price. Moreover, it is believed that the effect of mpg on price is different between domestic and foreign cars. Estimate a linear regression model based on the above description. All else being equal, what is the effect of one mile-per-gallon increase on the price of foreign car