Table 1.

Sample characterization according to sex, skin color, economic level and school category.

Sample characterization	Absolute frequency (n)	Relative frequency (%)
Sex
Male	215	47,7
Female	236	52.3
Skin color
White	299	66.3
Non-white	152	33.7
Economic level
High (Class A and B)	152	40.8
Intermediate (Class C)	169	45.2
Low (Class D and E)	52	14.0
School category
Private	126	27.9
Public	162	35.9
State	153	33.9
Federal	10	2.2