Question

Suppose a test for the presence of an inorganic phosphorus (IP) in a lake gives the following results: If a lake has the IP, the test returns a positive result 95% of the time. If a lake does not have the IP, the test still returns a positive result 7% of the time. Suppose 10% of the lakes contain the IP. According to Bayes theorem, what is the probability that a positive test result for a lake turns out to be a false positive?

Answer 1