Strata | Names of strata | Number of investigations |
Stratum 1 | Sidi Slimane―Sidi Yahya | 50 |
Stratum 2 | Oulad Ben Hammadi et Boumaiz | 50 |
Stratum 3 | Sfafaa et Kceibya | 50 |
Stratum 4 | Azghar et Dar Bel Amri | 50 |
Stratum 5 | M'Saada et Oulad H’Cine | 50 |
Stratum 6 | Ameur Chamalia | 50 |
| Sample | 300 |