In the past paper solution for this question, it seemed like the examiners used N as a negative binomial distribution, and the probability of an event as a binomial distribution. In order to get the expectation and variance of the total number of claims, I think they used the E[E[T|N]] and the (E[X])^2*V[N] + V[X]E[N]. But it seems that the mean of the neg. binomial distribution was squared instead of the mean of the binomial. Does anyone understand the examiners' answer to this question?
Thanks.
Thanks.