bution with numerator degrees of freedom <span class="emphasis"><em>df1</em></span>
          and denominator degrees of freedom <span class="emphasis"><em>df2</em></span>.
        </p>
<p>
          Requires that <span class="emphasis"><em>df1</em></span> and <span class="emphasis"><em>df2</em></span> are
          both greater than zero, otherwise <a class="link" href="../../error_handling.html#math_toolkit.error_handling.domain_error">domain_error</a>
          is called.
        </p>
<pre class="program