| Distribution of sample by sex and age | ||||
| n | % | Mean of age (SD) | Extended | |
| Girls | 284 | 39.8 | 17.42 (1.27) | 15 - 21 |
| Boys | 430 | 60.2 | 17.38 (1.60) | 15 - 21 |
| Total | 714 | 100 | 17.39 (1.47) | 15 - 21 |