| Value | Category | Cases | |
|---|---|---|---|
| 1 | boil it | 947 |
63.5%
|
| 2 | filter it | 93 |
6.2%
|
| 3 | add chemicals | 1 |
0.1%
|
| 4 | boil and filter it | 405 |
27.1%
|
| 5 | other | 46 |
3.1%
|
| Sysmiss | 308 |