action. If, for example, one wanted to calculate marginal effects on subsets of a data frame, those subsets can be passed directly to <code><a href="../reference/margins.html">margins()</a></code> via the <code>data</code> argument (as in a call to <code><a href="http://www.rdocumentation.org/packages/prediction/topics/prediction">prediction()</a></code>).</p>
<p>The rest of this vignette shows how to use <code>at</code> and <code>data</code> to obtain various kinds of marginal effects, and how to use plott