</dd>
<dt>age</dt><dd><p>the professor's age.</p>
</dd>
<dt>gender</dt><dd><p>factor indicating instructor's gender.</p>
</dd>
<dt>credits</dt><dd><p>factor. Is the course a single-credit elective (e.g., yoga, aerobics, dance)?</p>
</dd>
<dt>beauty</dt><dd><p>rating of the instructor's physical appearance by a panel of six students,
averaged across the six panelists, shifted to have a mean of zero.</p>
</dd>
<dt>eval</dt><dd><p>course overall teaching evaluation score, on
a scale of 1 (very unsatisfactory) 