Module 7 Assignment MBA 8350, Fall 2015 | Complete Solution

Module 7 Assignment
MBA 8350, Fall 2015

Discussion Questions: 15.26, 15.27
Analytical Questions: 15.4, 15.11, 15.20
Discussion Questions:
15.26: How can you evaluate whether collinearity exists in a model?
15.27: What is the difference between stepwise regression and best-subsets regression?
Analytical Questions:
15.4: Is the number of calories in a beer related to the number of carbohydrates and/or the percentage of alcohol in the beer? Data concerning 150 of the best-selling domestic beers in the US are stored in DomesticBeer. The values for three variables are included: the number of calories per 12 ounces, the alcohol percentage, and the number of carbohydrates (in grams) per 12 ounces.
a. Perform a multiple regression analysis, using calories as the dependent variable and percentage alcohol and the number of carbohydrates as the independent variables.
b. Add quadratic terms for alcohol percentage and number of carbohydrates.
c. Which model is better, the one in (a) or (b)?
d. Write a short summary concerning the relationship between the number of calories in a beer and the alcohol percentage and number of carbohydrates.
15.11: Using the data of Problem 15.4 on page 581, stored in DomesticBeer, perform a natural logarithmic transformation of the dependent variable (calories). Using the transformed dependent variable and the percentage of alcohol and the number of carbohydrates as the 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 assumptions are valid.
c. At the 0.05 level of significance, is there a significant relationship between the natural logarithm of calories and the percentage of alcohol and 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 best? Why?
15.20: Refer to problem 14.8 on page 531. Perform a multiple regression analysis using the data in GlenCove and determine the VIF for each independent variable in the model. Is there reason to suspect the existence on collinearity?