. 2013 May 1;42(5):522–528.

Table 2:

Mean scores: comparative results for five countries

Months	Sample	N	Communication		Gross motor		Fine motor		Problem-solving		Social–personal
Months	Sample	N	Mean	P-value	Mean	P-value	Mean	P-value	Mean	P-value	Mean	P-value
4	U^a	1380	51	.00	55	.00	49	.61	53	.42	51	.27
	N^b	176	50	.50	55	.00	50	.18	55	.00	50	.07
	S^c
	K^d	99	51.9	.02	51	1	45.9	.02	53.3	.52	48.6	.01
	I^e	657	49.5		51		48.7		52.6		51.6
8	U	1285	54	.00	50	1	54	.00	52	.00	51	.00
	N	165	53	.00	47	.00	56	.88	52	.00	51	.01
	S
	K	82	43.7	.00	48.4	.28	47.5	.00	47.5	.00	47.6	.00
	I	586	51.1		50		56.1		55		53
12	U	1091	42	.00	49	.32	49	.00	49	.00	45	.03
	N	145	42	.00	46	.01	52	.23	51	.01	44	.03
	S	34	39	.00	40	.00	46	.00	49	.04	38	.00
	K	125	43.2	.00	51.6	.15	48.8	.00	47.8	.00	41.2	.00
	I	672	48.3		49.7		53		53		46.5
16	U	976	49	.23	55	.65	52	.00	50	.00	48	.00
	N	146	42	.00	57	.01	54	.00	54	1	48	.02
	S	34	38	.00	52	.13	45	.00	46	.00	46	.07
	K	131	38.9	.00	55.9	.29	46.8	.00	46.6	.00	44.1	.00
	I	556	48.2		54.7		50.5		54		50.2
20	U	845	48	.00	55	1	54	.00	49	.00	53	.18
	N	138	47	.00	57	.00	52	.00	50	11.	51	.19
	S	56	38	.00	52	.08	50	.67	44	.00	47	.00
	K	144	39.3	.00	55.7	.46	45.3	.00	45.4	.00	50.4	.06
	I	494	50.9		55		49.4		51.4		52.2
24	U	820	50	.00	54	.00	53	.00	51	.29	52	.09
	N	128	53	.38	56	.00	53	.00	50	.66	51	1
	S	56	44	.00	50	.15	53	.00	48		48	.04
	K	144	48.9	.00	55.3	.00	48.3	.28	48.8	.08	48.5	.00
	I	554	53.9		52.4		47.4		50.4		51
30	U	562	56	.23	51	.00	50	.00	51	.00	53	.22
	N	134	57	.02	56	.00	50	.09	52	.06	53	.36
	S	86	54	.27	53	.84	53	.00	49		51	.18
	K	223	53.2	.01	53.4	.82	49.5	.10	51.1	.00	49.8	.00
	I	498	55.3		53.2		47.9		53.7		52.3
36	U	512	54	.11	55	.00	52	.00	55	.01	53	.00
	N	126	54	.25	56	.00	52	.00	54	.73	53	.00
	S	70	54	.44	52	.48	54	.00	48	-	51	.24
	K	226	54.8	.90	55.2	.01	53.3	.00	53.2	.48	50.1	.52
	I	548	54.9		53		49.1		53.7		49.6
48	U	336	56	.00	52	.30	44	.01	57	.00	49	.00
	N	100	56	.00	54	.00	50	.41	54	.00	56	.00
	S
	K	224	52.6	.04	52.5	.06	51.1	.00	52.1	.00	53.9	.00
	I	545	53.9		51.2		46.5		49.6		51.8
60	U	125	50	.00	52	.08	51	.00	51	.00	54	.53
	N	82	55	.46	55	.14	51	.00	52	.00	56	.00
	S
	K	321	50.6	.00	53.2	.40	52.7	.00	55.1	.00	54.1	.39
	I	481	54.5		53.8		43.7		46		53.5

^a.

U: US,

^b.

N: Norway,

^c.

S: Spain (Galicia),

^d.

K: Korea,

^e.

I: Iran