Answer:
0.193877
Step-by-step explanation:
The data given to us is
Pre-Employment Drug Screening Results
          Positive test result         Negative test result
          Drug Use Is Indicated       Drug Use Is Not Indicated
Subject Uses Drugs: Â Â Â Â Â Â 38 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 12
Subject Is Not a drug user: 19 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 29
Now the total of this is = 38+19+12+29= 98
Now the probability of false positive is = 19/98= 0.193877
The Subject Is Not a drug user  would suffer from a false positive. He is not a user and has a positive result.