TABLE 1.

Descriptive statistic of all measures.

	N	Mean	SD	Min	Max	Skewness	Kurtosis
Gender (male/female)	499	256/243
Age/months	488	120.77	3.48	112	133	0.16	−0.55
Cognitive variables
Non-verbal IQ (/60)	499	45.88	5.72	21	59	−0.77	0.97
RAN (/s)	499	13.86	2.85	8	25	0.79	0.81
Onset and rime deletion (/16)	499	14.23	2.16	6	16	−1.26	0.90
Phoneme deletion (/16)	499	12.30	3.01	0	16	−0.97	0.72
Morphological production (/30)	499	21.79	4.19	9	30	−0.51	0.07
Reading ability
Character recognition (/150)	499	120.70	12.41	69	143	−1.16	1.72
Arithmetic ability
Addition (/40)	499	26.23	4.17	10	37	−0.27	0.03
Subtraction (/40)	499	25.63	4.56	14	37	−0.13	−0.47
Multiplication (/40)	498	30.27	3.16	17	39	−1.14	2.13
Division (/40)	499	26.47	6.40	9	40	−0.39	−0.57
Blank filling (/40)	499	26.66	5.44	7	40	−0.57	0.72
Comparison (/40)	499	25.81	4.62	11	40	−0.26	0.49
Visual–spatial ability
Number continuation (/20)	499	15.26	1.84	10	20	−0.07	−0.22
Visual length (/24)	499	14.70	5.26	0	24	−0.83	−0.19
Figure counting (/21)	499	12.97	3.22	3	21	0.11	−0.00
Square counting (/28)	499	19.50	4.00	3	27	−0.67	0.37
Number connection (/200)	499	96.66	21.89	22	165	−0.13	0.35
Academic achievement
5th grade Chinese curriculum test (/100)	491	83.03	8.84	34	97	−1.77	5.70
5th grade Math curriculum test (/100)	492	87.58	8.54	37	100	−1.81	5.17
6th grade Chinese curriculum test (/100)	490	88.64	6.93	50	98	−2.09	6.55
6th grade Math curriculum test (/100)	490	84.65	12.67	20	100	−1.88	5.02