As a student you have probably noticed a curious phenomenon. Inevery class, there are some students who zip through exams and turntheir papers in while everyone else is still working. Otherstudents continue working until the very last minute. Have you everwondered what grades these students get? Are the students whofinish first the best in the class or are they simply concedingfailure? To answer this question, we carefully observed a recentexam and recorded the amount of time each student spent working (X)and the grade they received (Y). The data from the sample of n = 10students is below.
a) compute the Pearson correlation to measure the degree ofrelationship between the time spent writing the exam and the grade.Is the correlation statistically significant? State the nullhypothesis, use α = .05 two-tailed and include a summarystatement.
b) What percentage of variance in grades is predicted from timespent writing the exam?
| Student | Time(in minutes)-X | Exam Grade-Y |
1 | 54 | 75 |
| 2 | 38 | 91 |
| 3 | 60 | 70 |
| 4 | 44 | 94 |
| 5 | 60 | 76 |
| 6 | 40 | 89 |
| 7 | 57 | 92 |
| 8 | 52 | 81 |
| 9 | 45 | 88 |
| 10 | 49 | 90 |
