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. Author manuscript; available in PMC: 2016 Dec 1.
Published in final edited form as: Dev Psychol. 2016 Oct 27;52(12):2085–2098. doi: 10.1037/dev0000227

Table 1.

Means, Standard Deviations, and Correlations (N = 962)

Correlations
Variable Type/Variable Mean SD 1 2 3 4 5 6 7 8 9 10 11 12
Later Higher-Level/End of grade 4
1. Word-problem solving skill 16.06 5.34
2. Pre-algebraic knowledge 19.36 6.78 0.71
Intermediary/End of grade 2
3. Calculation accuracy 12.75 1.93 0.33 0.34
4. Calculation fluency 25.46 10.36 0.39 0.36 0.33
Foundational/Beginning of grade 2
5. Calculation skill 4.99 1.90 0.47 0.47 0.30 0.44
6. Word-problem solving skill 6.89 3.64 0.64 0.57 0.27 0.28 0.53
7. Number understanding 15.10 6.70 0.45 0.40 0.22 0.24 0.32 0.39
8. Reasoning 14.97 4.45 0.42 0.39 0.23 0.24 0.27 0.38 0.22
9. Language comprehension 16.82 4.70 0.45 0.33 0.09 0.11 0.18 0.45 0.28 0.27
10. Working memory 7.19 3.54 0.43 0.40 0.23 0.19 0.27 0.44 0.26 0.36 0.40
11. Attentive behavior 38.48 12.21 0.50 0.49 0.27 0.35 0.42 0.43 0.28 0.38 0.24 0.31
12. Processing speed 11.45 2.64 0.34 0.36 0.20 0.26 0.30 0.32 0.21 0.24 0.17 0.28 0.33

Note. Word-problem solving skill is Iowa Test of Basic Skill-Level 10-Math. Pre-algebraic knowledge is Test of Pre-Algebraic Knowledge. Calculation accuracy is Addition Strategy Assessment. Calculation fluency is Second-Grade Calculations Battery. Calculation skill is Wide Range Achievement Test-Arithmetic. Word-problem solving skill is Word Problems. Number understanding is Number Line Estimation (reverse scored). Reasoning is Wechsler Abbreviated Scale of Intelligence-Matrix Reasoning. Language comprehension is Woodcock Diagnostic Reading Battery-Listening Comprehension. Working memory is Working Memory Test Battery for Children-Listening Recall. Attentive behavior is Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Rating Scales. Processing speed is Woodcock-Johnson Tests of Achievement III-Visual Matching.