The scatter plot shows the relationship between the test scores of a group of students and the number of hours they play computer games in a week:
On a grid, Label Hours Playing Computer Games on x axis and Test Scores on y axis. The title of the graph is Test Scores and Computer Games. The scale on the x axis shows the numbers from 0 to 10 at increments of 1, and the scale on the y axis shows numbers from 0 to 100 at increments of 10. Dots are made at the ordered pairs 0, 90 and 0, 100 and 0.5, 89 and 1, 81 and 1, 95 and 1, 100 and 1.1, 85 and 2, 90 and 3, 81 and 3.5, 65 and 3.5, 75 and 5, 70 and 6, 55 and 6.5, 65 and 7, 52 and 7.5, 95 and 9, 65. The ordered pair 7.5, 95 is circled and labeled as B. All the other points are put in an oval and labeled as A.
Part A: What is the group of points labeled A called? What is the point labeled B called? Give a possible reason for the presence of point B. (5 points)
Part B: Describe the association between students' test scores and the number of hours they play computer games. (5 points)
Part A: The group of points labeled A is called a cluster or a data cluster. The point labeled B is called an outlier. A possible reason for the presence of point B could be that the student represented by that point is an exceptional case, such as having a natural aptitude for the subject or receiving extra tutoring.
Part B: The association between students' test scores and the number of hours they play computer games appears to be negative. As the number of hours playing computer games increases, the test scores tend to decrease. However, this association is not strictly linear, as there are some students with high test scores despite playing a significant number of hours of computer games. This suggests that other factors may also be influencing students' test scores besides the number of hours spent playing computer games.