The number of inhabitants of a village who are selected for jury service in the course of a 10-year period is a random variable with the distribution \(\operatorname { Po } ( 4.2 )\).
(a) Find the probability that in the course of a 10-year period, at least 7 inhabitants are selected for jury service.
(b) Find the probability that in 1 year, exactly 2 inhabitants are selected for jury service.
Explain why the number of inhabitants of the village who contract influenza in 1 year can probably not be well modelled by a Poisson distribution.