. Author manuscript; available in PMC: 2024 Jan 26.

Published in final edited form as: Dev Psychol. 2012 Mar 5;48(5):1229–1241. doi: 10.1037/a0027433

Table 5.

Correlations Between Tasks in Study 2 (N = 42)

Task	1	2	3	4
1. Spatial skill (CMTT; items correct of 22)	—
2. Vocabulary (PPVT-III standardized score)	.43^**	—
3. Number line knowledge (0–100 number line linear R²)^a	.49^**	.46^**	—
4. Approximate symbolic calculation (items correct of 16)	.47^**	.46^**	.66^***	—
5. Approximate nonsymbolic calculation (items correct of 16)	.10	−.11	.14	.05

Note. CMTT = children’s mental transformation task; PPVT-III = Peabody Picture Vocabulary Test–Third Edition.

These variables have been transformed using an arcsine transformation {2 × asin[sqrt(x)]}.

^**

p < .01.

^***

p < .001.