### Home > CCA2 > Chapter 12 > Lesson 12.1.3 > Problem 12-48

Governments and security companies are coming to rely more heavily on facial recognition software to locate persons of interest.

Consider a hypothetical situation. Suppose that facial recognition software can accurately identify a person 99.9% of the time, and suppose the suspect is among 200,000 facial images available to a government agency. When the software makes a positive identification, what is the probability that it is not the suspect? Homework Help ✎

Make a model for this situation.

If a person has been identified as the suspect, what is the probability that he or she is

*not*actually the suspect?

Use the model at right as a starting point.

Complete it by including the probabilities.

*P*(suspect) = ^{1}/_{200,000}. *P*(ID is correct) = 0.999.*P*(not the suspect) = ?. *P*(ID is not correct) = ?.

The desired outcome is a person who is not the suspect being incorrectly identified, or situation D.

The possible outcomes are situation D and the suspect being correctly identified, or situation A.