The real words
The confusion matrix
Call the thing we're looking for (fire, spam, subscriber) the positive case.
| Actually yes | Actually no | |
|---|---|---|
| Guessed yes | TPtrue positive good catch | FPfalse positive false alarm |
| Guessed no | FNfalse negative missed it | TNtrue negative correctly quiet |
Your class sheet puts guessed in rows and actual in columns. Some books swap them, so always read the labels.