. Author manuscript; available in PMC: 2013 Feb 1.

Published in final edited form as: J Exp Child Psychol. 2011 Sep 25;111(2):212–229. doi: 10.1016/j.jecp.2011.08.012

Table 1.

Bivariate correlations among the variables

Variable	1	2	3	4	5	6	7	8
	Tasks used for the cluster analyses
1. Fraction computation – 4^th	--
2. Fraction computation – 5^th	.66	--
3. Conceptual composite – 4^th	.67	.67	--
4. Conceptual composite – 5^th	.61	.69	.84	--
	Tasks used for external validity
5. Word problems – 4^th	.55	.50.	.67	.69	--
6. Word problems – 5^th	.60	.59	.72	.73	.76	--
7. Estimation of sums - 4^th	.43	.39	.50	.48	.44	.41	--
8. Estimation of sums - 5^th	.54	.57	.63	.59	.53	.57	.52	--

Table Note: All correlations signt (p < at most .05).