Let {N(t), t 0} be a Poisson process with rate . For i n and

Let {N(t), t ≥ 0} be a Poisson process with rate λ. For i ≤ n and s

(a) find P(N(t) = n|N(s) = i);

(b) find P(N(s) = i|N(t) = n).