Half percent of a population has a particular disease. A test is developed for the disease. The test gives a false positive 3% of the time and a false negative 2% of the time.

(a) What is the probability that joe (a random person) tests positive?

(b) Joe just got the bad news that the test came back positive; what is the probability that Joe has the disease?

I'm not sure what false positive and false negative mean, does test positive imply he has the disease?

So, the prob that joe tests positive will be 0.5%+3%?

and part b will be 0.5%+2%?