5. A community college announces that the correlation between college entrance exam grades and scholastic achievement was found to be –1.08. On the basis of this you would tell the college that
(a) the entrance exam is a good predictor of success.
(b) the exam is a poor predictor of success.
(c) students who do best on this exam will be poor students.
(d) students at this school are underachieving.
(e) the college should hire a new statistician.
6. A researcher finds that the correlation between the personality traits “greed” and “superciliousness” when both are measured on a numerical scale is –0.40. What percent of the variation in greed can be explained by the relationship with superciliousness?
(a) 0% (b) 16% (c) 20% (d) 40% (e) 60%
7. Scientists rated the activity level of fish at different temperatures (Celsius). A rating of 0 indicates no activity and a rating of 100 indicates extremely heavy activity. The data they collected are given in the table below.
Fish act. 82 65 62 90 51 79 87
Water temp. 21 24 29 18 29 22 20
Which of the following statements is true?
(a) The level of fish activity helps explain the water temperature. At low levels of fish activity, the water is cooler. As fish move around more, water temperature increases.
(b) Increasing the water temperature causes the fish to swim faster.
(c) As water temperature decreases, the level of fish activity increases somewhat constantly.
(d) The correlation coefficient, 0.91, indicates that there is a fairly strong positive linear relationship between level of fish activity and temperature.
(e) Based on our sample data, we can safely estimate that the level of fish activity would be about 34 at a temperature of 12