>
<li>
<code>vi</code>, sampling variances of the standardized mean
differences,</li>
<li>
<code>district</code>, district id which distinguishes among the
districts,</li>
<li>and <code>school</code>, that distinguishes among different schools
within the same district.</li>
</ul>
</div>
<div class="section level3">
<h3 id="frequentist-hierarchical-meta-analysis-with-metafor">Frequentist Hierarchical Meta-Analysis with
<code>metafor</code><a class="anchor" aria-label="anchor" href="#frequentist-hierarchical-