Table 1. Composition of the age-related groups of children with the mean, standard error.

Groups	Age range (years)	Mean age ±SE	Number of children	Number of girls	Number of boys
1	5–7	6.44±0.08	19	9	10
2	7–9	7.62±0.13	22	10	12
3	9–11	9.58±0.12	16	6	10
4	11–14	12.19±0.16	20	14	6
5	14–18	15.04±0.20	18	12	6