 of the data point,
expressed as <span class="math inline">\(\log(\lambda)=\mu\)</span>.
Given a single continuous covariate <span class="math inline">\(t\)</span>, the mean <span class="math inline">\(\mu\)</span> can be expressed as</p>
<p><span class="math display">\[\begin{equation}
  \mu = \alpha + r t
\end{equation}\]</span></p>
<p>This is equivalent to a multiplicative model for <span class="math inline">\(\lambda\)</span>, i.e.</p>
<p><span class="math display">\[\begin{equation}
  \lambda = \exp(\a