Solution
= Solution
Conditional independence makes the <log-likelihood>
$$
\ell(\theta)=\sum_{i=1}^n\log f_{x_i}(Y_i;\theta).
$$
A <maximum-likelihood estimator> is any $\widehat\theta\in\operatorname*{argmax}_{\theta\in\Theta}\ell(\theta)$. If the model has $q$ fitted real parameters, its <Akaike information criterion> is
$$
\boxed{\operatorname{AIC}=-2\ell(\widehat\theta)+2q.}
$$