## 12.5 Vocabulary terms

Also other names for the same term, and formulas.

• True positive ($$n_{11}$$)

• True negative ($$n_{22}$$)

• False positive, Type I error ($$n_{12}$$)

• False negative, Type II error ($$n_{21}$$)

• True positive rate (TPR), Recall, Sensitivity, probability of detection, power. P(predicted positive | total positive) $$\frac{\# True Positive}{\#Condition Positive}$$

• True negative rate (TNR), Specificity, selectivity. P(predicted negative | total negative) $$\frac{\# True Negative}{\# Condition Negative}$$

• False positive rate (FPR), fall-out, probability of false alarm. $$\frac{\# False Positive}{\# Condition Negative}$$

• False negative rate (FNR), miss rate. $$\frac{\# False Negative}{\# Condition Positive}$$

• Prevalence. $$\frac{\# Condition Positive}{\# Total Population}$$

• Accuracy. $$\frac{\# True Positive + \# True Negative}{\# Total Population}$$

• Balanced Accuracy: $$[(n_{11}/n_{.1}) + (n_{22}/n_{.2})]/2$$ - Adjusts for class size imbalances

• Positive Predictive Value (PPV), Precision. P(true positive | predicted positive) $$\frac{\# True Positive}{\# Predicted Condition Positive}$$

• False discovery rate (FDR). $$\frac{\# False Positive}{\# Predicted Condition Positive}$$

• False omission rate (FOR). $$\frac{\# False Negative}{\# Predicted Condition Negative}$$

• Negative predictive value (NPV). $$\frac{\# True Negative}{\# Predicted Condition Negative}$$

• F1 score. The harmonic mean of precision and recall. This ranges from 0 (bad) to 1 (good): $$\frac{2 * (Precision * Recall)}{Precision + Recall}$$