At time t = 0, you begin counting the arrivals of buses at a depot. The number of buses Ki that arrive between time i - 1 minutes and time i minutes, has the Poisson PMF
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And K1, K2,... are an iid random sequence. Let Ri = K1 + K2 +···+ Ki denote the number of buses arriving in the first i minutes.
(a) What is the moment generating function φKi (s)?
(b) Find the MGF φRi(s).
(c) Find the PMF PRi(r).
(d) Find E[Ri] and Var[Ri]