Unit 4: Probability Name: Date: _ Class Period: 4.5 The General Multiplication Rule and Tree Diagrams EVEN MORE Practice Worksheet Does the new hire do drugs? Many employers require prospective employees to take a drug test. A positive result on this test suggests that the prospective employee uses illegal drugs. However, not all people who test positive actually use illegal drugs. The test could result in a false positive. A negative test result could be a false negative if the person really does use illegal drugs. Suppose that 4% of prospective employees use drugs, and that the drug test has a false positive rate of 5% and a false negative rate of 10%. Choose a prospective employee at random. 1) Draw a tree diagram to represent the possible results of their drug test. 2) Find the probability that the employee's drug test is positive. 3) Find the probability that the employee's drug test is negative. 4) Given the drug test is positive, find the probability that the prospective employee is actually a drug user