/a></span><span class="op">(</span><span class="st">"Healthy"</span>, <span class="st">"Diseased"</span><span class="op">)</span><span class="op">)</span></span></code></pre></div>
<p>The resulting <code>FFTrees</code> object <code>heart.fft</code>
contains 7 FFTs that were fitted to the <code>heart.test</code> data. To
evaluate a tree’s predictive performance, we compare its predictions for
the un-trained <code>heart.test</code> data with their true criterion
values. Here is how we can apply the best tr