Table 2.
The top 10 most informative uni-grams, bi-grams, and Unified Medical Language System (UMLS) concepts for pneumonia identification according to χ2 and t statistics
| Uni-gram | Bi-gram | UMLS concept |
| χ2 Statistic | ||
| col | sputum cx | Microbial culture of sputum |
| tan | sputum culture | Sputum |
| coughs | h1n1 positive | Fluorescence Units |
| pneumo | acquired pneumonia | Structure of middle lobe of lung |
| sputum | positive h1n1 | Influenza preparation |
| consolidation | pneumonia continue | H1N1 |
| stacking | continue lpv | Influenza virus vaccine |
| cart | coarse mechanical | Novel H1N1 influenza |
| proning | continue oseltamivir | Oseltamivir |
| coccyx | treatment pneumonia | Infiltration |
| t Statistic | ||
| sputum | sputum cx | Microbial culture of sputum |
| suctioning | sputum culture | Sputum |
| h1n1 | continue lpv | Consolidation |
| ventilatory | h1n1 influenza | Infiltration |
| consolidation | acquired pneumonia | Influenza preparation |
| secretions | bacterial pneumonia | Influenza virus vaccine |
| lpv | continue oseltamivir | Pneumonia |
| coughing | decreased breath | Fluorescence Units |
| flu | positive h1n1 | Influenza |
| tachypneic | urine sputum | Decreased breath sounds |