-Suppose that. airplanes arrive at an airport according to a Poisson process at a rate of 3 per minute. a) What. is the probability at least 3 planes arrive in a one minute interval? b} \"-"hat is the probability that exactly 70 planes arrive in a halfhour inter val? e} If X = number of planes that arrive in an hour, what is E-[X(1 Kl]? EuXv at the skew for a Poisson with rate = A. You may nd the binomial expansion formula on page 836 useful for evaluating EHX m3]. d} The skew of a random variable is dened as Determine