 Plotting the best FFT on <em>test</em> data.
</p>
</div>
<p>We could have visualized the same tree by asking for
<code>plot(titanic.pred.fft, data = "test", tree = "best.test")</code>.
Note that the label of the bottom panel has now switched from “Accuracy
(Training)” to “Accuracy (Testing)”. Both the sensitivity and
specificity values have decreased somewhat, which is typical when using
a model (fitted on training data) for predicting new (test) data.</p>
<p>Let’s visualize the prediction perfor