Exercise 3.14 - Posterior predictive for Dirichlet-multinomial

For question (a). In this concrete case we have $K=27$, $N=2,000$, any component of $\alpha$ be $10$, and $N_{\text{e}}^{\text{old}}=260$. To derive $p(x_{2001}=\text{e}|𝒟)$, we resort to the deduction in Exercise 3.13:

For question (b), the independence between characters is still ignored, bringing no significant change to the computation: