Table 2 Sociodemographic characteristics of study sample.
| Variables | Girls (n = 1391) | Boys (n = 1913) | Total (n = 3304) |
|---|---|---|---|
| Average age (years) (SD) | 15.8 (1.1) | 16.1 (1.2)** | 16.0 (1.2) |
| Stratified distribution of classes (%) | |||
| Preparatory class | 195 (14.0) | 185 (9.6) | 380 (11.5) |
| 9th grade | 497 (35.7) | 773 (40.4) | 1270(38.4) |
| 10th grade | 367 (26.3) | 476 (24.8) | 843(25.5) |
| 11th grade | 332 (23.8) | 479 (25.0) | 811 (24.5) |
| Number (SD) of family members | 5.1 (2.0) | 5.3 (2.2)** | 5.2 (2.1) |
| Number of siblings (%) | n = 1358 (42.2) | n = 1857 (57.8)** | n = 3215 |
| None | 243 (17.9) | 291 (15.7) | 534 (16.6) |
| 1–3 | 709 (52.2) | 923 (49.7) | 1632 (50.8) |
| >4 | 406 (29.9) | 643 (34.7) | 1049 (32.6) |
| Birth order (SD) | 2.3 (1.6) | 2.5 (1.8)** | 2.4 (1.7) |
| Socioeconomic level of family (%) | n = 1361 (42) | n = 1880 (58)** | n = 3241 |
| Poor | 310 (22.8) | 586 (31.2) | 896 (27.6) |
| Satisfied | 962 (70.7) | 1217 (64.7) | 2179 (67.2) |
| Good | 89 (6.5) | 77 (4.1) | 166 (5.1) |
| Number (%) immigrated past year | 156 (11.4) | 319 (16.9)* | 475 (14.6) |
| Not living with families (%) | 58 (4.2) | 121 (6.4)* | 179 (5.4) |
| Mean (SD) age of mothers | 40.5 (5.3) | 40.9 (6.1)* | 40.7 (5.8) |
| Number (%) separated from mothers | 17 (1.2) | 28 (1.4) | 45 (1.4) |
| Number (%) of illiterate mothers | 218 (15.8) | 405 (21.4)** | 623 (18.9) |
| Number (%) of unemployed mothers | 1123 (81.3) | 1614 (85.3)* | 2737 (83.6) |
| Mean (SD) age of fathers | 45.1 (6.0) | 45.3 (6.3) | 45.3 (6.2) |
| Number (%) separated from fathers | 67 (4.9) | 110 (5.7) | 177 (5.4) |
| Number (%) of illiterate fathers | 45 (3.4) | 115 (6.4) | 160 (5.1) |
| Number (%) of unemployed fathers | 194 (14.5) | 311 (17.2)* | 505 (16) |
Differences between two sexes *p<0.05; **p<0.001. The % figures represent the ratio of columns.