Table 3.
Do differences between student and professional grading vary with time in the term?
| a. Spring 2005 | ||||
|---|---|---|---|---|
| Week 5 | Week 10 | t statistic | p value (two-tailed) | |
| Mean difference: Individual students versus professional | 0.89 ± 0.18 (96) | 1.81 ± 0.17 (94) | −3.64 | 0.0003 |
| b. Autumn 2005 | |||||
|---|---|---|---|---|---|
| Week 2 | Week 5 | Week 10 | F value | p value (two-tailed) | |
| Mean difference: individual students versus professional | 0.46 ± 0.12 (100) | 1.61 ± 0.14 (100) | 1.9 ± 0.21 (100) | 21.93 | <<0.0001 |
Means are reported with SEs; sample sizes (numbers of practice exams graded) are in parentheses; the results are based on an unpaired t test in part (a) and an ANOVA in part (b).