Table 2.

Descriptive Statistics and Correlations for Students without a Learning Disability (n=14,146)

Measure	1	2	3	4	5	6	7	8
1. Grade 1, SAT-9	1
2. Grade 2, SAT-9	.62	1
3. Grade 3, SAT-10	.60	.70	1
4. Grade 4, SAT-10	.53	.62	.71	1
5. Grade K, PPVT	.37	.44	.44	.36	1
6. Grade 1, PPVT	.41	.48	.50	.42	.75	1
7. Grade 2, PPVT	.44	.52	.54	.46	.69	.75	1
8. Grade 3, PPVT	.44	.52	.55	.48	.63	.70	.75	.1
Scale Scores a (SAT-9/SAT-10) or Standard Scores b (PPVT-III)
Mean	566.46	608.42	640.20	653.09	96.20	97.42	99.06	101.00
SD	44.21	34.62	39.29	33.32	13.48	14.04	13.77	12.87
Minimum	415	423	483	497	40	40	40	40
Maximum	667	729	763	776	147	160	160	160
Skewness	0.23	0.11	0.22	−0.10	−0.07	−0.04	−0.27	−0.41
Kurtosis	−0.32	0.49	0.07	0.32	0.66	0.09	0.51	1.67
Z-scores
Mean	0.05	0.98	1.68	1.96	−0.91	0.01	0.84	1.62
SD	0.97	0.76	0.87	0.73	0.97	1.00	1.01	0.95
Minimum	−3.28	−3.12	−1.78	−1.48	−5.10	−4.96	−4.53	−4.41
Maximum	2.27	3.63	4.38	4.67	2.82	5.23	5.60	5.80

Note. SAT-9 = Stanford Achievement Test-9, Reading Comprehension; SAT-10 = Stanford Achievement Test-10, Passage Comprehension. PPVT = Peabody Picture Vocabulary Test. All correlations significant at p < .01.

^aScale scores were only available for the SAT in the original database.

^bStandard scores were only available for the PPVT values in the original database.

We used a reverse look-up procedure using the reference tables in the technical manual to estimate raw scores (see Methods section or contact first author for more information on this procedure).