t>
<dd><p>confidence level; the default is <code>0.95</code>.</p></dd>


<dt>vcov.</dt>
<dd><p>Optional coefficient covariance matrix, or a function to compute the covariance matrix, to use in computing the model summary.</p></dd>


<dt>df</dt>
<dd><p>Optional residual degrees of freedom to use in computing model summary.</p></dd>


<dt>x</dt>
<dd><p>An object of class <code>"ivreg"</code> or <code>"summary.ivreg"</code>.</p></dd>


<dt>newdata</dt>
<dd><p>Values of predictors for which to obtain predicted 