```
set.seed(123)
lvls = c("a", "b")
truth = factor(sample(lvls, 20, replace = TRUE), levels = lvls)
response = factor(sample(lvls, 20, replace = TRUE), levels = lvls)
confusion_matrix(truth, response, positive = "a")
confusion_matrix(truth, response, positive = "a", relative = TRUE)
confusion_matrix(truth, response, positive = "b")
```

Run the code above in your browser using DataCamp Workspace