(1) In each of the following scenarios, determine if the data are paired (yes or no)

(a) Compare pre- (beginning of the semester) and post-test (end of the semester) scores for the same group of students.

(b) Assess the gender-related salary gap by comparing salaries of randomly sampled men and women.

(c) Compare artery thicknesses at the beginning of a study and after 2 years of taking Vitamin E for the same group of patients.

(d) Assess the effectiveness of a diet regimen by comparing the before and after weights of subjects.

(e) We would like to know if Intel's stock and Southwest Airlines' stock have similar rates of return. To find out, we take a random sample of 50 days and record Intel's and Southwest's stock on those same days.

(f) We randomly sample 50 items from Target stores and note the price for each. Then we visit Walmart and collect the price for each of those same 50 items to see if there is significant difference.

(g) A school board would like to determine whether there is a difference in average SAT scores for students at one high school versus another high school in the district. To check, they take a simple random sample of 100 students from each high school.

(2)A first sample of 28 men who were recovering from a heart attack and a second independently selected sample of 30 men who had not had a heart attack was taken with the goal of comparing mean cholesterol levels. The men in the samples were the same age. Researchers were investigating whether the mean cholesterol for the men who were recovering from heart attacks would be higher than the mean level for the other men.

The means and the standard deviations for the two groups are shown below.

(2)A first sample of 28 men who were recovering from a heart attack and a second independently selected sample of 30 men who had not had a heart attack was taken with the goal of comparing mean cholesterol levels. The men in the samples were the same age. Researchers were investigating whether the mean cholesterol for the men who were recovering from heart attacks would be higher than the mean level for the other men. The means and the standard deviations for the two groups are shown below. Sample N Mean StDev Sample 1 28 253.9 47.7 Sample 2 30 193.1 22.3