15.19 The authors of the paper “Beyond the Shooter Game:

Examining Presence and Hostile Outcomes among Male Game Players” (Communication Research [2006]: 448–466)

studied how video-game content might influence attitudes and behavior. Male students at a large Midwestern university were assigned at random to play one of three action-oriented video games. Two of the games involved some violence—one was a shooting game and one was a fighting game. The third game was a nonviolent race car driving game.

After playing a game for 20 minutes, participants answered a set of questions. The responses were used to determine values of three measures of aggression:

(1) a measure of aggressive behavior; (2) a measure of aggressive thoughts; and (3) a measure of aggressive feelings.

The authors hypothesized that the means for the three measures of aggression would be greatest for the fighting game and lowest for the driving game.

a. For the measure of aggressive behavior, the paper reports that the mean score for the fighting game was significantly higher than the mean scores for the shooting and driving game, but that the mean scores for the shooting and driving games were not significantly different. The three sample means were:

Driving Shooting Fighting Sample mean 3.42 4.00 5.30 Use the underscoring procedure of this section to construct a display that shows any significant differences in mean aggressive behavior score among the three games. (Hint: See Example 15.7.)

b. For the measure of aggressive thoughts, the three sample means were Driving Shooting Fighting Sample mean 2.81 3.44 4.01 The paper states that the mean score for the fighting game only significantly differed from the mean score for the driving game and that the mean score for the shooting game did not significantly differ from either the fighting or driving games. Use the underscoring procedure of this section to construct a display that shows any significant differences in mean aggressive thoughts score among the three games.