When $\alpha_i=\alpha$, the <law of total variance> gives
$$
\operatorname{Var}(Y_i)=\mu_i+\alpha\mu_i=(1+\alpha)\mu_i.
$$
This is the quasi-Poisson mean-variance relation with constant dispersion, so the most appropriate printed p-value is $0.0982$ from model2.

Solution

Past exam of the mathematics course of the University of Cambridge / 2025 / iii / Paper 218 / 1 / e / ii / Solution

 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2025/iii/paper-218/1/e/ii/solution