Students observed that when they played violent video games, they experienced an increase in heart rate. one student group conducted an experiment using five classmates as subjects. students predicted that playing a violent video game would increase heart rate more than watching a violent movie. the students collected baseline data while the subjects sat still, breathing deeply. for the first stimulus, the students played a violent war-type video game for ten minutes. they rested for ten more minutes, and then watched the landing during d-day from the movie "saving private ryan".
materials:
~vernier computer interface : to record and interact with the data statistics.
~vernier heart rate monitor
~ video of movie
~interactive video game

the initial heart rates, shown next to subject number in the graph, was taken wearing noise canceling headphones, with subject's eyes closed.
each participant was subjected to the stimuli in this order: baseline, video game, movie scene. the date collected in shown here:

what would be an appropriate research question for this experiment?
a) does any kind of violence cause an increase in human heart rate?
b) what type of stimuli will substantially increase your heart rate?
c) will playing violent video games increase your heart rate more than watching a violent movie?
d) will students remain calmer when at rest, listening to music or will they become agitated when playing a violent game?

the students concluded that playing violent video games caused a greater increase in heart rate than watching a violent movie. some of the students thought the results of the study to be inconclusive. can you site a reason why some students may feel this way?
a) only five subjects were tested; they should test a larger group of randomly chosen subjects.
b) there was only one control situation; the design should include at leas two control situations.
c) they did not test other ways to increase heart rate as a method of comparison: running, exercising, walking alone in the dark.
d) they did not test situations that one would expect to lower heart rate, like playing soothing music or letting students pet a kitten