Customers arrive to the store according a Poisson process with intensity λ = 1 customers per hour. Let N[0,t] be the number of arrivals between [0,t]. (a) Find the probability P(N[0,2] = 2,N[2,3] = 1|N[0,6] = 6). (b) Let Ti be the arrival time of the ith costumer. Calculate Cov(T2,T4).