Table 2.
Distributions of IQ and grade- and age-based WIAT-III test scores for children with verbal and nonverbal IQ > 70 (N=668; percents listed in Z-score columns).
| Z-score | ≤ -2 | > -2, ≤ -1 | > -1, ≤ 1 | > 1 |
|---|---|---|---|---|
| Normal distribution | 2.3% | 13.7% | 68.2% | 15.8% |
| IQ | ||||
| Verbal IQ | 0 | 21 | 70 | 9 |
| Nonverbal IQ | 0 | 24 | 69 | 6 |
| Grade-Based Academic Achievement | ||||
| Word Reading | 2 | 15 | 68 | 15 |
| Numerical Operations | 3 | 24 | 67 | 6 |
| Pseudoword Decoding | 4 | 16 | 69 | 11 |
| Spelling | 2 | 12 | 71 | 14 |
| Age-Based Academic Achievement | ||||
| Word Reading | 2 | 14 | 68 | 16 |
| Numerical Operations | 3 | 24 | 66 | 7 |
| Pseudoword Decoding | 5 | 17 | 68 | 11 |
| Spelling | 3 | 19 | 65 | 14 |