Using the data of Problem 15.4 on page 637, stored in Domesticbeer, perform a square-root transformation on each of the independent variables (percentage alcohol and number of carbohydrates). Using calories as the dependent variable and the transformed independent variables, perform a multiple regression analysis.
a. State the regression equation.
b. Perform a residual analysis of the results and determine whether the regression model is valid.
c. At the 0.05 level of significance, is there a significant relationship between calories and the square root of the percentage of alcohol and the square root of the number of carbohydrates?
d. Interpret the meaning of the coefficient of determination, r2, in this problem.
e. Compute the adjusted r2.
f. Compare your results with those in Problem 15.4. Which model is better? Why?