Question

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?

Answer 1

(100% - 5%)*20 = 19;

p = 19/20 = 0.95 ;