sector</code> records the type of each worker’s job; levels for <code>sector</code> include clerical, manufacturing, sales, service. etc.</p>
<p>In the following subsections, we compare the shapes of several models, all of which use <code>wage</code> as the response variable.</p>
<section id="one-explanatory-variable" class="level3 page-columns page-full">
<h3 class="anchored" data-anchor-id="one-explanatory-variable">One explanatory variable</h3>
<p>First, consider models with a single explanatory variab