Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Demographic characteristics of complete sample at W1 and W2
| W1 | W2 | |
| N | 512 | 456 |
| Boys | 49% | 48% |
| Left-handed | 13% | 12% |
| AXIS I disorder* | 2.1% | 1.8% |
| SES*,† low–middle–high | 9%–46%–45% | 7%–46%–47% |
| Age (SD) | 7.94 (0.67) | 9.98 (0.69) |
| Age range | 7.02 to 9.68 | 8.97 to 11.68 |
| Mean IQ* (SD) | 103.58 (11.76) | 103.81 (11.63) |
| IQ range | 72.50 to 137.50 | 72.50 to 137.50 |
At W1.
Social economic status (SES), based on parental education.
