Your firm is considering a mandatory drug testing of all employees. To assess the costs (resources for testing and possible morale problems) and benefits (a more productive work force), you have decided to study the probabilities of various outcomes on a per- worker basis. The laboratory has provided you with some information, but not everything you need to know. Using a probability tree, you hope to compute the missing, helpful information.

The testing procedure is not perfect. The laboratory tells you that if an employee usesdrugs, the test will be "positive" with probability 0.90. Also, for employees who do not use drugs, the test will be "negative" (that is "not positive") 95% of the time. Based onthe informal poll of selected workers, you estimate that 8% of your employees use drugs.

Calculate the probability that a randomly selected worker is a

Q1."drug user and testspositive" a) 0.05 b) 0.072 c) 0.6101 d) 0.118

Q2.."not a drug user and testspositive"a) 0.05 b) 0.072 c) 0.6101 d) 0.046

Q3."has a positive test result"a) 0.05 b) 0.072 c) 0.6101 d) 0.118

Q4."tests positive given that he/she is not adrug user"a) 0.05 b) 0.072 c) 0.6101 d) 0.118

Q5."drug user giventhat he/she testspositive"a) 0.05 b) 0.072 c) 0.6101 d) 0.118