Table 1.

Descriptive statistics and correlations for all variables

	Skewness	Range	M ± SD	1	2	3	4	5	6	7
1 Gender -		–	–	1
2 Age1	0.21	–	4.69 ± 0.33	0.06	1
3 SP1	1.31	0–10	2.30 ± 2.14	−0.02	0.34**	1
4 VP2	−0.45	7–15	11.93 ± 1.89	−0.05	0.27*	0.34*	1
5 SP2	0.82	0–12	4.14 ± 2.47	−0.04	0.34**	0.68***	0.39**	1
6 VP3	−0.12	11–20	15.78 ± 1.82	−0.11	0.14	0.54***	0.39**	0.54***	1
7 SP3	0.22	0–12	5.28 ± 2.96	0.05	0.36**	0.55***	0.46***	0.76***	0.52***	1

N = 64; Age 1 = age at T1; SP1 = Arithmetic story problems at T1; VP2 = Visual perception at T2; SP2 = Arithmetic story problems at T2; VP3 = Visual perception at T3; SP3 = Arithmetic story problems at T3. ^*** p < 0.001, ^** p < 0.01, ^* p < 0.05