
Prior probability (odds): 
24% (0.3) 

POSITIVE TEST: 
Positive Likelihood ratio: 
81 
95% confidence interval: 
[11,568] 
Posterior probability (odds): 
96% (25.1) 
95% confidence interval: 
[77%,99%] 
(~ 1 in 1.0 with positive test 
are sick) 

NEGATIVE TEST: 
Negative Likelihood ratio: 
0.04 
95% confidence interval: 
[0.01,0.27] 
Posterior probability (odds): 
1% (0.0) 
95% confidence interval: 
[0%,8%] 
(~ 1 in 1.0 with negative test 
are well) 

Odds = Probability / (1Probability) 
+LR = Sensitivity / (1  Specificity) 
LR = (1  Sensitivity) / Specificity 
Posterior Odds = Prior Odds x LR 
