There are several measures of performance that we can compute from the preceding table:
The true positive rate (or sensitivity) is computed as the number of true positives divided by the number of true positives plus the number of false negatives. In our example, sensitivity is the probability that a survivor is classified as such. Sensitivity in this case is:
168 / (168 + 186) = 0.4745763
The true negative rate (or specificity) is computed as the number of true negatives divided by the number of true negatives plus the number of false positives. In our example, specificity is the probability that a nonsurvivor is classified as such. Specificity in this case is:
645 / (645 + 60) = 0.9148936
The positive predictive value (or precision) is computed as the number of true positives divided by the number of true positives plus the number of false positives. In our example, precision is the probability that individuals classified as survivors are actually...