Are gas prices driving elections? The Chance Web site discusses the use of regression to predict the margin of victory in presidential elections since 1948 from the price of gas (in 2008 dollars). Read the article at www.causeweb.org/wiki/chance/ index.php/Chance_News_72. Use the data in the article to do the following.
(a) Fit a simple linear regression model using gas price to predict margin of victory. Do your results agree with those reported in the article?
(b) Use the incumbent party as an indicator variable (code Democrats as 1 and Republicans as 0), and add this to your simple linear regression model. What is the value of R2 ?
(c) Now add gross domestic product (GDP) to your regression model in (b). What is the value of R2 ?