Participants were assigned to watch one of three types of TV programs, with nine commercials embedded in each show. Group V watched a TV program with a violent content code rating (e.g., Tour of Duty); group S viewed a show with a sex content code rating (e.g., Strip Mall); and group N watched a neutral TV program with neither a V nor an S rating (e.g., Candid Camera). The dependent variable measured for each participant was a score (y) on his/her recall of the brand names in the commercial messages, with scores ranging from 0 (no brands recalled) to 9 (all brands recalled).
a. Write a model for E(y) as a function of viewer group.
b. Fit the model, part a, to the data saved in the file. Give the least squares prediction equation.
c. Conduct a test of overall model utility at α = .01. Interpret the results.
d. The sample mean recall scores for the three groups were V = 2.08, S = 1.71, and N = 3.17. Show how to find these sample means using only the β estimates obtained in part b.
For information: Refer to the Journal of Applied Psychology (June 2002) study of recall of television commercials, Exercise 9.28.