on the method chosen.
<code>tidy</code> returns one row for each estimated effect, either
with groups depending on the <code>effects</code> parameter.
It contains the columns</p>
<dl><dt>group</dt>
<dd><p>the group within which the random effect is being estimated: <code>NA</code> for fixed effects</p></dd>
<dt>level</dt>
<dd><p>level within group (<code>NA</code> except for modes)</p></dd>
<dt>term</dt>
<dd><p>term being estimated</p></dd>
<dt>estimate</dt>
<dd><p>estimated coefficient</p></dd>
<dt>std.err