suppose that when a transistor of a certain type is subjected to an accelerated life test, the lifetime x (in weeks) has a gamma distribution with mean 24 weeks and standard deviation 12 weeks. (a) what is the probability that a transistor will last between 12 and 24 weeks? (b) what is the probability that a transistor will last at most 24 weeks? (c) is the median of the lifetime distribution less than 24? why or why not?