f the following columns:</p><ul>
<li><p><code>date</code>: a calendar date</p></li>
<li><p><code>weekday</code>: a day of the week</p></li>
<li><p><code>percentage</code>: a share of non-missing observations for a given
          day</p></li>
<li><p><code>sign_stat</code>: a sign test statistic</p></li>
<li><p><code>sign_signif</code>: a significance of the statistic</p></li>
</ul>

    <h2 class="hasAnchor" id="details"><a class="anchor" href="#details"></a>Details</h2>

    <p>This test is application of 