The time to failure in hours of an electrical circuit subjected to a high temperature has a Weibull distribution with parameters a = 3 and λ = 0.5.
(a) What is the median failure time of a circuit?
(b) The circuit engineers can be 99% confident that a circuit will last as long as what time?
(c) What are the expectation and variance of the circuit failure times.
(d) If a circuit has three equivalent backup circuits that have independent failure times, what is the probability that at least one circuit is working after three hours?