spop:</strong> change in crspop</p></li>
<li><p><strong>cseason:</strong> change in season</p></li>
<li><p><strong>hsperc:</strong> percentile in h.s.</p></li>
<li><p><strong>football:</strong> =1 if football player</p></li>
</ul></div>
    <div id="source">
    <h2>Source</h2>
    <p><a href="https://www.cengage.com/cgi-wadsworth/course_products_wp.pl?fid=M20b&amp;product_isbn_issn=9781111531041" class="external-link">https://www.cengage.com/cgi-wadsworth/course_products_wp.pl?fid=M20b&amp;product_isbn_iss