Suppose you are interested in the role of exercise in maintaining cardiac health among young adult women between the ages of 25 and 35. You ask 60 patients to record the number of days they exercise in a month to see whether frequency of exercise correlates with systolic blood pressure.

You decide to use the computational formula to calculate the Pearson correlation between the number of days of exercise in a month and systolic blood pressure. To do so, you call the number of days of exercise in a month X and the systolic blood pressure Y. Then, you add up your data values (X and Y), add up the squares of your data values (X and Y), and add up the products of your data values (XY). The following table summarizes your results:

X- 690

Y- 7,290

X- 12,496

Y- 902,296

XY- 82, 281

1. The sum of squares for the number of days of exercise in a month is SSx = ___.

2. The sum of squares for systolic blood pressure is SSy= ___.

3. The sum of products for the number of days of exercise in a month and systolic blood pressure is SP = ___.

4. The Pearson correlation coefficient is r = ___.

5. Suppose you want to predict systolic blood pressure from the number of days of exercise in a month among young women. The coefficient of determination is r = _1_, indicating that _2_ of the variability in the systolic blood pressure can be explained by the relationship between the systolic blood pressure and the number of days of exercise in a month.

1a. -0.18 b. 0.03 c. 0.82 d. -0.072

2a. 97 b. 0.03% c. 3% d. 1,800%

6. When doing your analysis, suppose that, in addition to having data for the number of days of exercise in a month for these young women, you have data for the number of days they did notexercise in a month. You'd expect the correlation between the number of days they did notexercise in a month and the number of days of exercise in a month to be _1_ and the correlation between the number of days they did notexercise in a month and systolic blood pressure to be _2_.

1a. positive b. negative

2a. positive b. negative