Suppose that a test for opium use has a 2% false positive rate and a 5% false negative rate. That is, 2% of people who do not use opium test positive for opium, and 5% of opium users test negative for opium. Furthermore, suppose that 1% of people actually use opium. Required:
a. Find the probability that someone who tests negative for opium use does not use opium.
b. Find the probability that someone who tests positive for opium use actually uses opium.