Important Biostatistics and Epidemiology Equations Sensitivity = TP / (TP + FN) = true positives / disease present Specificity = TN / (FP + TN) = true negatives / disease absent Positive Predictive Value = TP / (TP + FP) = true positives / all positives Negative Predictive Value = TN / (FN + TN) = true negatives / all negatives Positive Likelihood Ratio = Sensitivity / (1 – Specificity) Negative Likelihood Ratio = (1 – Sensitivity) / Specificity Sensitivity vs Specificity Mnemonic: - Sensitivity = SNOUT = Rule OUT - Specificity = SPIN = Rule IN #Biostatistics #statistics #Epidemiology #Equations #calculations #diagnosis #mnemonic #sensitivity #specificity #PPV #NPV
