fault value is <code>NULL</code>.</p></dd>


<dt>siteID</dt>
<dd><p>Character value providing name of the site ID variable in
the <code>dframe</code> data frame.  For a two-stage sample, the site ID variable
identifies stage two site IDs.  The default value is <code>NULL</code>, which
assumes that each row in <code>dframe</code> represents a unique site.</p></dd>


<dt>weight</dt>
<dd><p>Character value providing name of the design weight
variable in <code>dframe</code>.  For a two-stage sample, the
weight 