Probability
posted by Betty .
Suppose that 3% of the population ha a certain disease. We have a test for the disease. 97% of those who actually have the disease will test positive. 12% of those who do not have the disease will also test positive. What is the probability that a randomly selected person has the disease and tests positive?

Probability of both/events occurring is found by multiplying the probabilities of the individual events.
.03 * .97 = ?