Data set: Movies 

The file Movies contains the ratings and genres of movies that came out in 2008. This is simply an observational study, as clearly movie producers do not try to create an equal number of G, PG, and R movies each year. 

a. Write a statistical model that predicts gross earnings based on Genre and Rating. Use α_i to represent the effect of Rating and β_j to represent the effect of Genre. The sample size varies for every group. 

b. Use statistical software to test for the effects of Rating and Genre. Do not include an interaction term. Check the model assumptions, perform any necessary transformations, and state your conclusions. 

c. Try to use statistical software to test for the effects of Rating, Genre, and Rating*Genre. The analysis cannot be conducted because many of the interaction factor combinations have no observations. Group several of the Genre variables so that there are at least two observations in each Rating*Genre group. Now use your new groupings to test for the effects of Rating, Genre, and Rating*Genre.