An Engineering Project Involves Reinforcing a Concrete Beam

Multiple Choice

An engineering project involves reinforcing a concrete beam. From previous experience it is thought that the probability of corrosion is 1%. A diagnostic test is performed on the reinforced beam. If corrosion is present, then the probability that the test will reveal it is 80% while the probability that the test will miss it is 20%. The diagnostic never yields false positives-that is, it will never indicate corrosion if corrosion is not present. What is the probability of discovering corrosion?

A) 0.001
B) 0.008
C) 0.09
D) 0.8
E) 0.002