According to the laws of Aryan math the answer is (((Kauffman))). I probably confuse "False positive rate" with something else. I was thinking the prevalence is irrelevant to the question and the question could be rewritten as: > If a test to detect a disease ~~whose prevalence is 1 out of 1,000~~ has a false positive rate of 5 percent, what is the chance that a person found to have a positive result actually has the disease? cut > If a test to detect a disease has a false positive rate of 5 percent, what is the chance that a person found to have a positive result actually has the disease? Question makes complete sense (no?) and 95% is the obvious answer. **Update:** I misunderstood *false positive rate*. A rate is **per** something, I assumed **per positive test result** but seems it's **per all tests**. That's right, right?