The gross state product (GSP) is the sales of all goods and services originating in a state minus the costs of any goods or services used to generate the sales. The file State GSP contains the 2015 GSP for all 50 U.S. states along with several other variables, including gasoline prices, the 2015 population estimate, 2014 median household income, and the political party of the state’s governor. (See the Description Tab on the data file for sources for these variables.)
a. Develop a correlation matrix for the variables in this data file. Identify the variable that has the highest correlation with the GSP variable.
b. Construct a simple linear regression model for explaining the variation in state GSP using the highest correlated independent variable. Test whether the regression coefficient for this variable is statistically significant using alpha = 0.05.

c. Construct a multiple linear regression model using state GSP as the dependent variable. What percent of the variation does the model explain?
d. Referring to the model developed in part c, indicate whether the overall model is significant and which, if any, of the independent variables, are significant. Use alpha = 0.05.
e. Construct a 95% confidence interval estimate for the regression coefficient on the dummy variable, governor political party, and interpret.