#10 1. We predict that while listening to classical music, students asked to complete mental tasks will complete more tasks than will students listening to rock music. We recruited 30 students into our study. Fifteen students were asked to complete mental tasks while listening to classical music. Their mean number of tasks completed was 23.13 and the variance was 8.55. The other 15 students were asked to complete mental tasks while listening to rock music. Their mean number of tasks completed was 20.87 and the variance was 12.55. Did those who listened to classical music complete significantly more tasks than those who listened to rock music? 2. We want to know if there is a difference in anxiety level between patients being treated with behavioral therapy and patients being treated with insight therapy. We selected 12 students being treated with behavioral therapy and measured their anxiety as a score on an anxiety inventory. We selected 12 students being treated with insight therapy and also measured their anxiety as a score on an anxiety inventory. For the behavioral group, the mean was 4.25 and the variance was 8.932. For the insight therapy group, the mean was 1.133 and the variance was 5.879. 3. A research report described the results from a study that counted how many minutes someone could run on the treadmill after consuming McDonald's Big Macs daily for a week and the number of minutes someone could run on the treadmill who ate salad every day for a week. Twenty-three participants were recruited. The t-statistic for the independent-groups test was t=1.71. Was there a significant difference between the number of minutes run on the treadmill between the two groups? State in terms of the null hypothesis. 4. We wanted to see if drinking a Starbucks beverage could improve mood, we gathered 9 participants and assesses their mood before drinking Starbucks and then after drinking a Starbucks beverage. The mean of the difference scores was D = 4 and a variance of s2 = 36. a. What was the observed t-statistic? b. Did drinking a Starbucks beverage improve our participants' moods? 5. A researcher conducts a repeated-measures study to evaluate a treatment with a sample of n = 16 participants and obtains a t statistic of t = 1.94. a. Would he reject or accept the null if his hypothesis is that the drug will have some kind of effect? b. Would he reject or accept the null if his hypothesis is that the drug will improve patients' conditions? 6. We believe that people watched less television on Election than on the day before Election Day. We had 7 participants and we tracked how many hours of TV they watched on each day. Did they watch significantly less TV on Election Day? Participant A B C D E F G Day Before Election Day 15 11 6 2 2 12 1 On Election Day 6 15 9 11 8 11 3 \f\f\f\f