Millions of Americans are subjected to drug testing in the workplace. The tests are not always reliable. A false positive rate of 5% is considered to be a conservative estimate. Suppose that there are 20 employees in your company, which tests its workers weekly. 1) What is the probability of no false-positives for this week’s test?
(100% - 5%)*20 = 19; p = 19/20 = 0.95 ;