Answer Happy

2. . In Canada, the Supreme Court recently ruled that employees can be tested for drugs only if management has reasonable cause to administer the test. A false positive occurs when a drug test administered to a non-drug user yields a positive result. A false negative occurs when a drug test administered to a drug user yields a negative result. (a) Suppose that 5% of a population of workers consists of drug users. The drug test has a false positive rate (i.e., the probability of a positive drug test given the worker is a non-drug user) of 5% and a false negative rate (i.e., the probability of a negative drug test given the worker is a drug user) of 5%. A worker selected from this population is drug tested and found to have a positive result. Using Bayes theorem, calculate the probability that the worker is a non-drug user? (10) (b) Now suppose that 95% of a population of workers consists of drug users. Again, assume that the false positive rate and false negative rate of the drug test are 5%. A worker selected from this population is drug tested and found to have a positive result. Using Bayes theorem, calculate the probability that the worker is a non-drug user? (10) (20)