1. A group of researchers investigated the impact of every-other-day fasting on weight loss in humans. After 22 days of every-other-day fasting, the researchers measured the amount of weight that was lost by each of 16 human subjects. These data were used to construct a 95% confidence interval for the mean weight loss for the population of people who followed the every-other-day fasting diet for 22 days. The computed interval was 4.1 0.7 pounds. The interpretation of the interval given by the researchers was, with 95% confidence, we can infer that a randomly selected person from the population who follows the every-other-day fasting diet for 22 days would lose between 3.4 and 4.8 pounds.Why is the researchers' interpretation of the confidence interval incorrect?

a) Because anything could happen for the people on the diet; some could lose less than 3.4 or more than 4.8 pounds.

b) Because the confidence interval estimates the weight loss for the sample, and not the weight loss for the population.

c)Because the confidence interval estimates the population mean weight loss and not an individual's weight loss.

d) Because 95% of people who follow the diet will be in this range, losing between 3.4 and 4.8 pounds.

2. One hundred student-athletes attended a summer camp to train for a particular track race. All 100 student-athletes followed the same training program in preparation for an end-of-camp race. Fifty of the student-athletes were randomly assigned to additionally participate in a weight-training program along with their normal training (the training group). The other 50 student-athletes did not participate in the additional weight-training program (the non-training group). At the end of the summer camp, all 100 student-athletes ran the same race and their individual times (in seconds) were recorded.The mean speed of the training group was 44 seconds, and the mean speed of the non-training group was 66 seconds.The standard deviation for the non-training group was 20 seconds. Consider the following possible values for the standard deviation of the training group. Which of these values would produce the strongest evidence of a difference between the two groups?

a) 10 seconds

b) 20 seconds

c) 30 seconds