dd><p>an object of class <code>formula</code> as might be passed to 
<code>lm</code>, <code>glm</code>, or <code>coxph</code>. Functions of variables, specified using <code><a href="dummy.html">dummy</a></code>
or <code><a href="polynomial.html">polynomial</a></code> may also be included in <code>formula</code>.</p></dd>


<dt>data</dt>
<dd><p>a data frame, matrix, or other data structure with matching
names to those entered in <code>formula</code>.</p></dd>


<dt>intercept</dt>
<dd><p>a logical value
indic