> You find someone with a positive score. What's the chance they have it? Did you remember to consider the really tricky and counterintuitive conditional proba

> You find someone with a positive score. What's the chance they have it? Did you remember to consider the really tricky and counterintuitive conditional probability for this? P('has the rare illness' | 'is at doctor's appointment with at least partially matching set of symptoms') Assuming here that the doctor isn't just testing everyone for the rare illness.