In Exercises, refer to Table, included with the Chapter Problem. In each case, assume that 1 of the 1000 test subjects is randomly selected.
Inverse Probabilities
a. Find P (negative test result  subject does not use drugs).
b. Find P (subject does not use drugs  negative test result).
c. Compare the results from parts (a) and (b). Are they equal?
Table PreEmployment Drug Screening Results

Positive Test Result (Drug Use Is Indicated) 
Negative Test Result (Drug Use Is Not Indicated) 
Subject Uses Drugs 
44 (True Positive) 
6 (False Negative) 
Subject Is Not a Drug User 
90 (False Positive) 
860 (True Negative) 
Solution 22BSC
= 0.993