In a regression based on 30 annual observations, U.S. farm income was related to four independent variables-grain exports, federal government subsidies, population, and a dummy variable for bad weather years. The model was fitted by least squares, resulting in a Durbin-Watson statistic of 1.29. The regression of e2i on y`i yielded a coefficient of determination of 0.043.
a. Test for heteroscedasticity.
b. Test for autocorrelated errors.