Table A1.
Demographics
| Variable | Subsample n=1,074 |
Full Sample n=2,332 |
|---|---|---|
| Mean Age (SD) | 11.63 (2.70) | 11.63 (2.63) |
| % Female | 52% | 50% |
| % Monozygous Twins | 31% | 32% |
| % Siblings of Twins | 9% | 8% |
| % Primary Caregiver Caucasian | 87% | 88% |
| Median Years of Mother's Educationa | 14 | 14 |
| Median Years of Father's Educationb | 12 | 12 |
| Mean Full Scale IQ (SD) | 107.84 (12.72) | 107.37 (12.97) |
| % History of Reading Problems in School | 29% | 31% |
| % Meeting Symptom Criteria for ADHD | 23% | 24% |
a
14 years=Associate's Degree or Equivalent
b
12 years=High School Graduate or Equivalent