Cognitive ability (average range) | Test | Average (standard deviation) | Min–max | Skewness | Kurtosis |
---|---|---|---|---|---|
Children | |||||
 Phonological awareness (10 ± 3) | Elision, CTOPP (scaled score) | 9.00 ± 1.55 | 7–12 | 0.892 | − 0.694 |
Blending words, CTOPP (scaled score) | 7.90 (0.94) | 6–10 | 0.204 | 0.087 | |
Digit memory, CTOPP (scaled) | 7.60 (2.99) | 2–14 | 0.020 | − 0.049 | |
 Verbal ability (100 ± 15) | Verbal IQ, WPSSI (scaled score) | 25.45 (5.99) | 14–36 | − 0.209 | − 0.644 |
 Nonverbal ability (100 ± 15) | Performance IQ, WPSSI (scaled score) | 23.10 (7.40) | 10–38 | − 0.168 | − 0.350 |
 General ability (100 ± 15) | Full scale IQ, WPSSI (composite) | 91.65 (11.77) | 74–120 | 0.654 | 0.472 |
Mothers | |||||
 Maternal reading ability (100 ± 10) | Sight word efficiency, TOWRE (scaled) | 92.24 (9.67) | 71–106 | − 0.422 | − 0.429 |
Phonemic decoding efficiency, TOWRE (scaled) | 92.86 (10.49) | 71–110 | − 0.346 | − 0.543 | |
 Maternal depression | BDI–II (total average score across 3 years) | 15.14 (11.80) | 3–45 | 1.29 | 0.74 |