html">prob</a></code>.</p></dd>


<dt>by</dt>
<dd><p>A character code specifying 1 or 2 perspective(s)
that split(s) the population into 2 subsets.
Specifying 1 perspective plots a frequency tree (single tree)
with 3 options:</p><ol><li><p><code>"cd"</code>: by condition only;</p></li>
<li><p><code>"dc"</code>: by decision only;</p></li>
<li><p><code>"ac"</code>: by accuracy only.</p></li>
</ol><p>Specifying 2 perspectives plots a frequency prism (double tree)
with 6 options:</p><ol><li><p><code>"cddc"</cod