Table 1.
Results of paired t tests: Practice exams graded by individual students versus a professional grader
| Mean score: peer grading | Mean score: professional grading | n | t statistic | p value (two-tailed) | |
|---|---|---|---|---|---|
| Spring 2005: Week 5 | 6.90 ± 0.20 | 6.00 ± 0.20 | 96 | −4.95 | <<0.0001 |
| Spring 2005: Week 10 | 6.45 ± 0.25 | 4.64 ± 0.21 | 94 | −10.43 | <<0.0001 |
| Autumn 2005: Week 2 | 6.71 ± 0.18 | 6.25 ± 0.20 | 100 | −3.73 | 0.0003 |
| Autumn 2005: Week 5 | 6.45 ± 0.18 | 4.84 ± 0.16 | 100 | −11.45 | <<0.0001 |
| Autumn 2005: Week 9 | 7.3 ± 0.16 | 5.4 ± 0.20 | 100 | −9.02 | <<0.0001 |
Ten points were possible on each exercise; means are reported with SEs.