Table 1.

Mean Age (standard deviation), Total Sample Size, and Sex Distribution in U.S./Australia and Scandinavia at the End of Kindergarten, Grade 1, and Grade 2.

Characteristics	U.S./Australia	Scandinavia
End of Kindergarten
Age (in months)	74.4 (4.0)	81 (3.5)
Total sample size	750	230
Girls (%)	51	49
End of Grade 1
Age (in months)	87.3 (4.6)	92.9 (3.7)
Total sample size	735	182
Girls (%)	49	50
End of Grade 2
Age (in months)	99.6 (4.8)	105.1 (3.6)
Total sample size	686	140
Girls (%)	51	50