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

Question

Quizplus · Accepted Answer

The probability of discovering corrosion is the probability of corrosion occurring (1%) times the probability of the test revealing it if it is present (80%), which is 0.01 * 0.8 = 0.008.

An Engineering Project Involves Reinforcing a Concrete Beam