(5p) After including income in the regression, we do not know for certain that the coefficients on the indicator variables are jointly significant. Perform a linear hypothesis test for this purpose and paste the call and response below. What is the alternative hypothesis? How many restrictions are part of this test? Are the coefficients on the categorical variables jointly significant at the 5% level? Do we reject the null hypothesis? (g) (5p) Drawing on your own personal familiarity with the subject, identify at least two items that are currently part of the error term, u, that you would consider attempting bring into the regression directly. For each, mention if you expect that data on the item would be available or identify a correlated variable for which the data might be available