TABLE 1.
Descriptive statistics for variables measured at senior kindergarten and grade one.
| Variables | Measures | Maximum | Mean (SE) | Range | Reliability | |
| Kindergarten | General cognitive abilities | Nonverbal IQ | 140 | 116.55 (1.23) | 90.00–140.00 | 0.75 |
| Sustained attention | – | 639.06 (9.24) | 449.45–946.89 | 0.85 | ||
| Inhibitory control | – | 1221.92 (77.15) | 444.31–5,412.48 | 0.83 | ||
| Visual processing | Orientation discrimination task | – | 7.51 (0.69) | 2.32–27.46 | 0.79 | |
| Mathematics | Calculation | 49.00 | 15.40 (0.80) | 0–49.00 | 0.89 | |
| Word problems | 24.00 | 14.67 (0.73) | 1.00–24.00 | 0.99 | ||
| Character reading | Character recognition | 1006.18 | 371.82 (33.67) | 12.12–997.48 | 0.99 | |
| Grade one | Calculation | 49.00 | 25.83 (1.01) | 7.00–49.00 | 0.90 | |
| Word problems | 24.00 | 20.26 (0.57) | 7.00–24.00 | 0.99 | ||
| Character reading | Character recognition | 1006.18 | 743.01 (29.33) | 99.31–1,006.18 | 0.99 |
The range in sustained attention and inhibitory control means reaction time (ms).