The scatter graph shows the time spent revising (hours) and the exam score (%) for 12 students.
| Revision (hours) | Exam Score (%) |
|---|---|
| 2 | 28 |
| 3 | 35 |
| 4 | 45 |
| 5 | 42 |
| 6 | 58 |
| 7 | 65 |
| 8 | 72 |
| 9 | 85 |
| 10 | 82 |
| 11 | 92 |
| 12 | 95 |
| 13 | 98 |
a.[1]
What type of correlation does the scatter graph show?
b.[2]
Another student revised for 8.5 hours8.5\text{ hours}8.5 hours. Estimate the exam score for this student.