(iii) For n < n1, calculate the probability function fz(z) = P(Z = z) using only convolution and the probability functions fx(x) = P(X = x) and fy(y) = P(Y = y). The following formula may help: ∑[fx(x) * fy(z - x)] for k < min(b, c) and u < s < g and marks.
(iv) Write down an expression for fz(z) = P(Z = 2) when n1 < z < n2 (assuming n1 = n2) and u > n. You do not need to evaluate these expressions. mark.