Table 3. Tests of intelligence and academic attainments.
|
Early group
|
Late group
|
Early vs. late
|
||
|---|---|---|---|---|
| Test | X (SD) | X (SD) | t test | P value |
| Wechsler Intelligence Scales | ||||
| Verbal IQ | 93.0 (11.87) | 86.4 (15.50) | 0.80 | 0.44 |
| Performance IQ | 88.5 (23.16) | 81.0 (18.45) | 0.58 | 0.57 |
| Full-scale IQ | 89.5 (18.79) | 82.2 (16.05) | 0.68 | 0.51 |
| Verbal IQ Subtests: Information, vocabulary, comprehension | 9.0 (1.74) | 7.0 (3.10) | 1.28 | 0.25 |
| WORD | ||||
| Basic reading | 96.8 (6.31) | 92.6 (18.50) | 0.53 | 0.61 |
| Spelling | 87.8 (7.96) | 87.8 (17.80) | 0.00 | 1.00 |
| Reading comprehension | 87.7 (11.76) | 85.0 (11.20) | 0.38 | 0.71 |
| WOND | ||||
| Math reasoning | 90.4 (8.93) | 81.5 (11.03) | 1.34 | 0.22 |
| Numerical operations | 98.4 (11.63) | 83.0 (6.56) | 2.06 | 0.08 |
Scores are means (X) and SDs. Means (±SDs) for normal subjects on the Wechsler Intelligence Scales, WORD, and WOND are 100 (±15). Means (±SDs) for normal subjects on the three verbal IQ subtests, which provide a measure of semantic memory, are 10 (±3).