notes a vector. Although <code>beta</code> could have
been declared as a matrix, an array of vectors (or a two-dimensional
array) is more efficient for accessing rows; see the <a href="indexing-efficiency-section.html#indexing-efficiency.section">indexing
efficiency section</a> for more information
on the efficiency tradeoffs among arrays, vectors, and matrices.</p>
<p>This model can be further sped up and at the same time made more
arithmetically stable by replacing the application of inverse-logit
inside 