[QIO] The time between arrivals of small aircraft at a county airport is exponentially distributed with a mean of one hour. (a) What is the probability that more than two aircraft arrive within an hour? (b) If 30 separate one-hour intervals are chosen, what is the probability that no interval contains more than three arrivals?

The life (in hours) of a magnetic resonance imagining machine (mri) is modeled by a weibull distribution with parameters β = 2 and δ = 370 hours. (a) determine the mean life of the mri. (round your answer to 2 decimal ) determine the variance of the life of the mri. (round your answer to 1 decimal ) what is the probability that the mri fails before 250 hours? (round your answer to 4 decimal places.)