></span>
<span class="r-wrn co"><span class="r-pr">#&gt;</span> <span class="warning">Warning: </span>Removed 1 rows containing non-finite values (`stat_boxplot()`).</span>
<span class="r-plt img"><img src="gr_plot_periods-2.png" alt="" width="960" height="593"></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="co"># calculate test beforehand</span></span></span>
<span class="r-in"><span><span class="va">tests</span> <span class="op">=</span> <span class="fu"><a href="gr_t