Suppose that a drug test for an illegal drug is such that it is 98% accurate in the case of a user of that drug (i. e., it produces a positive result with probability 0.98 in the case that the tested individual uses the drug) and 90% accurate in the case of a non user of the drug (i. e., it is negative with probability 0.90 in the case that the person does not use the drug). Suppose that 10% of the entire population uses this drug. Required:
a. What is the probability that the individual test positive for using illegal drugs?
b. What is the probability that a person who tested positive for this job itâs actually a non-user?