4. A researcher was interested in testing whether alertness levels differed in those who drank a cup of coffee versus those who drank an energy drink. She randomly assigned participants to one of the two conditions and then showed them a five-minute video. After the video, all participants completed a questionnaire measuring their memory for things that had been presented in the video. Higher scores = better recall. Perform an appropriate two-tailed test of the significance of the mean difference. Coffee = 1 Energy drink = 2 Group Recall score 1 45 1 38 1 40 1 35 2 37 2 49 2 36 2 47 Hypotheses: tobs = tthreshold= df = Conclusion