>> Basic Statistics
Experience shows that X, the number of customers entering a post office during any period of time t, is a random variable the probability mass function of which is of the form
p(i) = k (2t)i/i! ; i = 0; 1; 2; : : :
(a) Determine the value of k.
(b) Compute P(X < 4) and P(X > 1).