Question

21. A company producing electric relays has three manufacturing plants producing 50, 30, and
20 percent, respectively, of its product. Suppose that the probabilities that a relay
manufactured by these plants is defective are 0.02, 0.05, and 0.01, respectively.
(a) If a relay is selected at random from the output of the company, what is the probability
that it is defective?
(b) If a relay selected at random is found to be defective, what is the probability that it was
manufactured by plant 2?

Answer 1

Answer:

D. 0.027.Explanation: Let be the event that the electric relay is defective. Let Ai i = 1 2 3 be the event that the electric relay is manufactured in plant i.