ChaoBao Insurance Company prices its cyber-risk coverage using the following assumptions for commercial policy-

holder Alpha-Z:

1. In any month, there can be at most 1 cyber attack on Alpha-Z's computer systems, and such an attack occurs

with probability 0.02.

2. The number of cyberattacks on Alpha-Z in any month is statistically independent of the number of attacks in all

other months.

For any m{1,2,...}, let Am denote the number of cyberattacks on Alpha-Z in the next m months.

(a) FindPr{12>4|A6= 2}.

(b) Find Var[A18|A12= 4]/E[A18|A12= 4]