• anonymous
the known rate of usage of a particular illicit drug is 3% (a random sample of the population would find that 3% of the people are currently using the drug.) a test exists that will correctly identify a drug user 96% of the time. the test also misidentifies a non user (a false positive) 2% of the time. what is the probability that a person who has tested posiitive for the drug is actually a non-user.
  • Stacey Warren - Expert
Hey! We 've verified this expert answer for you, click below to unlock the details :)
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
  • katieb
I got my questions answered at in under 10 minutes. Go to now for free help!
  • anonymous
So for a randomly selected individual, the chance that they'll test positive is: .03*.96 + .97*.02 = .0482 (that's true positives plus false positives) The chance of getting a false positive is: .97*.02 = 0.0194 so, given that someone tests positive, the chance that it's a false positive is: .0194/.0482 = .4025 = 40.25%

Looking for something else?

Not the answer you are looking for? Search for more explanations.