对于癌症检测的例子来说，y=1代表有癌症
Precision/Recall
| Actual | class | ||
| 1 | 0 | ||
| Predicted | 1 | True positive | False Positive |
| class | 0 | False negative | True negative |
\[\Pr ecision = \frac{{True \bullet positive}}{{predicted \bullet positive}} = \frac{{True \bullet positive}}{{True \bullet positive + Fake \bullet positive}}\]