Originally Posted by

**DAI&DF**
I'm having some trouble with these...

A test for Hepatitis A is 98% accurate: if a person has Hepatitis, the test will come out "positive" with 0.98 probability, and if a person doesn't have Hepatitis, the test will come out "negative" with 0.98 probability. The percentage of the population that has Hepatitis A is 0.005. Based on these probabilities, if a person tests positive for Hepatitis A, what is the probability that the person actually has Hepatitis A?

I got the answer for this by doing 0.98 * .005 = .0049, but it seems too easy of a calculation. Did I do this correctly?