Table 2.
Descriptive statistics for working memory, intelligence, and reading comprehension and mathematics performance for Grades 1 through 6 and for the total sample in Study 1
| Monkey Game (Verbal WM, Mean Proportion Correct Scores) | Lion Game (Visual–Spatial WM, Mean Proportion Correct Scores) | Raven’s SPM (Raw Sum Scores) | Reading Comprehension (Ability Scores) | Mathematics Performance (Ability Scores) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | Mean | SD | n | Mean | SD | n | Mean | SD | n | Mean | SD | n | Mean | SD | |
| Grade 1 | 664 | .38 | .16 | 745 | .46 | .18 | 810 | 24.65 | 7.60 | – | – | – | 762 | 34.71 | 16.07 |
| Grade 2 | 730 | .46 | .15 | 758 | .56 | .18 | 799 | 31.19 | 8.26 | 647 | 14.13 | 14.91 | 777 | 53.23 | 15.39 |
| Grade 3 | 644 | .51 | .14 | 751 | .65 | .17 | 818 | 35.79 | 7.65 | 728 | 26.27 | 13.23 | 722 | 73.77 | 15.15 |
| Grade 4 | 727 | .57 | .12 | 744 | .71 | .15 | 785 | 39.97 | 7.08 | 654 | 32.12 | 13.64 | 758 | 86.79 | 13.67 |
| Grade 5 | 700 | .58 | .13 | 787 | .74 | .13 | 793 | 42.07 | 6.58 | 720 | 46.56 | 15.35 | 766 | 100.90 | 12.00 |
| Grade 6 | 711 | .62 | .13 | 801 | .77 | .13 | 852 | 44.09 | 5.97 | 730 | 56.26 | 19.23 | 787 | 110.22 | 14.75 |
| Total | 4,176 | .52 | .16 | 4,586 | .65 | .19 | 4,857 | 36.33 | 9.86 | 3,480 | 35.60 | 21.44 | 4,572 | 76.75 | 30.15 |
WM = working memory, SPM = Standard Progressive Matrices