## Quick Question

This question asks about the following two confusion matrices:

Confusion Matrix #1:

Predicted = 0 | Predicted = 1 | |
---|---|---|

Actual = 0 | 15 | 10 |

Actual = 1 | 5 | 20 |

Confusion Matrix #2:

Predicted = 0 | Predicted = 1 | |
---|---|---|

Actual = 0 | 20 | 5 |

Actual = 1 | 10 | 15 |

What is the sensitivity of Confusion Matrix #1?

Explanation

The sensitivity of a confusion matrix is the true positives, divided by the true positives plus the false negatives. In this case, it is 20/(20+5) = 0.8

What is the specificity of Confusion Matrix #1?

Explanation

The specificity of a confusion matrix is the true negatives, divided by the true negatives plus the false positives. In this case, it is 15/(15+10) = 0.6

## Quick Question

To go from Confusion Matrix #1 to Confusion Matrix #2, did we increase or decrease the threshold value?

Explanation

We predict the outcome 1 less often in Confusion Matrix #2. This means we must have increased the threshold.