Table 1 The number of samples in the study area
| County name | Number of rice milling factories | The area under cultivation (In acres) | Required sample size |
|---|---|---|---|
| Bandar gaz | 6 | 2650 | 4 |
| Kordku | 8 | 6408 | 8 |
| Bandar torkeman | 4 | 515 | 4 |
| Agh ghala | 6 | 4543 | 6 |
| Gorgan | 18 | 5209 | 7 |
| Ali Abad | 7 | 6200 | 6 |
| Azadshahr | 12 | 5275 | 7 |
| Gonbad | 8 | 6530 | 8 |
| Ramian | 6 | 1819 | 4 |
| Minoodasht | 11 | 4985 | 7 |
| Kalaleh | 4 | 970 | 4 |
| Total | 90 | 45,714 | 69 |