Suppose that the longevity of a light bulb is exponential with a mean lifetime of eight years.(a) Find the probability that a light bulb lasts less...

months

(e) If a light bulb has lasted seven years, what is the probability that it fails within the eighth year. (Round your answer to four decimal places.)

5

3)P(X < 1) = 1 — exp(—1/)6) = 1 — 12-0-13 = 1 — 0.882497 = 0.117503 av. 0.118 P(X < 1) = 0.113 b) P(7 < X < 9) =P(X <9)—P(X< 7) = (1 — eXP(-9/fi)) — (1 —...