Table 1. Means (SDs) on selection and background variables for four groups.
| Test | Group | TD | RD | LI | LI + RD | Anova output |
|---|---|---|---|---|---|---|
| N | 117 | 67 | 32 | 37 | ||
| % male | 40 | 49 | 56 | 68 | ||
| Nonverbal ability | ||||||
| WASI block design | Mean | 97.8 | 99.1 | 95.3 | 96.9 | F(3, 246.6) = 0.9 |
| SD | 11.87 | 11.93 | 10.99 | 11.57 | p = .439 | |
| Language | ||||||
| WASI vocabulary | Mean | 98.2a | 93.3b | 83.0c | 78.9c | F(3, 223.7) = 33.37 |
| SD | 13.17 | 13.05 | 11.53 | 12.39 | p < .001 | |
| WJ understanding directions | Mean | 99.6a | 95.9a | 78.2b | 83.9b | F(3, 246.9) = 31.56 |
| SD | 13.57 | 13.62 | 12.88 | 13.35 | p < .001 | |
| ERRNI comprehension | Mean | 98.6a | 98.8a | 91.8b | 88.0b | F(3, 242) = 6.87 |
| SD | 14.55 | 14.65 | 14.13 | 14.48 | p < .001 | |
| ERRNI MLU | Mean | 102.1a | 97.6a | 89.5b | 87.8b | F(3, 224.1) = 11.53 |
| SD | 15.47 | 15.72 | 15.2 | 15.22 | p < .001 | |
| NEPSY sentence repetition | Mean | 97.1a | 92.0b | 81.1c | 74.7d | F(3, 243.6) = 38.66 |
| SD | 13.12 | 13.16 | 12.01 | 12.71 | p < .001 | |
| Reading | ||||||
| TOWRE word reading | Mean | 102.6a | 71.4c | 97.6b | 68.9c | F(3, 242.8) = 150.84 |
| SD | 11.54 | 11.61 | 11.2 | 11.48 | p < .001 | |
| TOWRE phonemic decoding | Mean | 101.2a | 75.0c | 95.3b | 73.1c | F(3, 247.1) = 114.37 |
| SD | 11.06 | 11.15 | 10.53 | 11.1 | p < .001 | |
| Family background | ||||||
| SES index | Mean | −0.01 | −0.06 | −0.24 | −0.21 | F(3, 252) = 1.36 |
| SD | 0.710 | 0.710 | 0.584 | 0.693 | p = .255 |
Notes.
- TD
- Typically developing
- RD
- Reading disabled
- LI
- Language impaired
Means with different superscripts differ significantly at the .05 level on LSD test after adjustment of degrees of freedom for twin as random factor.