ights</dt>
<dd><p>vector indicating
optional weights for weighted regression.</p></dd>


<dt>subset</dt>
<dd><p>vector indicating a subset
to be used for all inference.</p></dd>


<dt>robustSE</dt>
<dd><p>a logical indicator
that standard errors (and confidence intervals) are to be computed using the Huber-White sandwich
estimator. The default is TRUE.</p></dd>


<dt>conf.level</dt>
<dd><p>a numeric scalar
indicating the level of confidence to be used in computing confidence
intervals. The default is 0.95.<