up manufacturer </span>
<span class="r-out co"><span class="r-pr">#&gt;</span>                   3.370000                   2.988889 </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> </span>
<span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/stats/wilcox.test.html" class="external-link">wilcox.test</a></span><span class="op">(</span><span class="va">emission</span> <span class="op">~</span> <span class="va">company</span>, data <span class="op">=</span> <span class="va">Monoxi