During the Olympics, all athletes must pass a mandatory drug test administered by the International Olympic Committee before they are permitted to compete. Currently the IOC is using a test that is 99% accurate. In the past, athletes use drugs such as steroids and marijuana at the rate of about 1 athlete per 100.
1. Out of 20,000 athletes, about how many can be expected to test positive for drugs?
2. Of the athletes that test positive, about how many actually use drugs?
3. What is the probability that an athlete that tests positive actually uses drugs?
4. How could the drug test be improved so that there is a higher probability that and athlete uses drugs given a positive test result?