15.7 The paper “Women’s and Men’s Eating Behavior Following Exposure to Ideal-Body Images and Text”

(Communication Research [2006]: 507–529) describes an experiment in which 74 men were assigned at random to one of four treatments:

1. Viewed slides of fit, muscular men 2. Viewed slides of fit, muscular men accompanied by diet and fitness-related text 3. Viewed slides of fit, muscular men accompanied by text not related to diet and fitness 4. Did not view any slides The participants then went to a room to complete a questionnaire. In this room, bowls of pretzels were set out on the tables. A research assistant noted how many pretzels were consumed by each participant while completing the questionnaire. Data consistent with summary quantities given in the paper are given in the accompanying table.

Do these data provide convincing evidence that the mean number of pretzels consumed is not the same for all four treatments? Test the relevant hypotheses using a significance level of .05.

Treatment 1 Treatment 2 Treatment 3 Treatment 4 8 6 1 5 7 8 5 2 4 0 2 5 13 4 0 7 2 9 3 5 1 8 0 2 5 6 3 0 8 2 4 0 11 7 4 3 5 8 5 4 1 8 5 2 0 5 7 4 6 14 8 1 4 9 4 1 10 0 0 7 6 6 0 3 3 12 12 5

6 10 8

Treatment 1 Treatment 2 Treatment 3 Treatment 4 6 2 10