eturn a multiple-partial
F-test involving <code>var1</code> and <code>var2</code>. If an F-statistic will already be 
calculated regardless of the <code><a href="U.html">U</a></code> specification,
then any naming convention specified via <code>name ~ var1</code> will be ignored.
The multiple partial tests must be the last terms specified in the model (i.e. no other predictors can
follow them).</p>
    </div>
    <div class="section level2">
    <h2 id="see-also">See also<a class="anchor" aria-label="anchor