Table 4.

Descriptive statistics of the cognitive skill measures for the US children.

	Mean	Standard deviation	Range
Age (years), N=54	7.97	1.67	4.9–11.2
Phonological awareness, N=46	107.4	15.6	85–151
Phonological memory, N=48	96.3	9.9	79–127
Rapid automatic naming, N=21	102.6	12.6	85–124
Grey oral reading test, accuracy, N=42	9.1	4.3	1–17
Grey oral reading test, comprehension, N=42	11.8	3.4	5–19
Grey oral reading test, fluency, N=42	10.1	4.3	1–18
Tests of word reading efficiency, total, N=43	107.6	20.3	66–146
Tests of word reading efficiency, phonemic, N=43	106.8	16.9	79–140
Tests of word reading efficiency, sight, N=43	105.9	18.1	59–138
Peabody picture vocabulary test, N=52	113.4	11.1	95–139
Performance IQ, N=43	109.6	14.2	79–138
Verbal IQ, N=44	110.7	13.7	61–151