Distribution of the total population of Dezful schoolchildren in the 2004–2005 school year and the study participants in groups of grade level, gender and area of residence
| Total population of Dezful schoolchildren | Participants | ||
|---|---|---|---|
| No (%) | No (%) | ||
| Grade level | 1 | 6495 (7.8) | 398 (7.2) |
| 2 | 6515 (7.8) | 411 (7.4) | |
| 3 | 6469 (7.7) | 410 (7.4) | |
| 4 | 7181 (8.6) | 484 (8.7) | |
| 5 | 7851 (9.5) | 570 (10.3) | |
| 6 | 8966 (10.7) | 454 (8.2) | |
| 7 | 8197 (9.8) | 425 (7.7) | |
| 8 | 8877 (10.7) | 521 (9.4) | |
| 9 | 8841 (10.6) | 877 (15.8) | |
| 10 | 6618 (8.0%) | 586 (10.6) | |
| 11 | 6061 (7.2) | 281 (5.7) | |
| 12 | 1179 (1.4%) | 127 (2.3) | |
| Gender | male | 43 441 (52.1) | 2440 (44.0) |
| female | 39 809 (47.9) | 3104 (56.0) | |
| Area of residence | urban | 55 840 (67) | 3730 (67.3) |
| rural | 27 410 (33) | 1814 (32.7) | |
| Total | 83 250 | 5544 | |