Answer:
When the machine indicates a lie, what is the probability that the suspect is really lying? If the machine does not indicate a lie, what is the probability that the suspect is really telling the truth?
My solution if the probability that a test subject is chosen at random from the 200 in fact lie = 80/(80+5)=0.94
Then when 15% of people arrested lie, the probability that the suspect is really lying is 0.15*0.94=0.141
