| mattress → cause back → pain | 14 |
| mattress → contribute to → back pain | 3 |
| mattress → lead to → back pain | 3 |
| mattress → cause → backache | 3 |
| negative | neutral | positive |
| 0.805 | 0.184 | 0.011 |
| Raw frequency | 23 |
| Normalized frequency | 0.288 |
| Modifier score | 0.000 |
| Perplexity | 160.450 |