.attr("checked", "checked") not working in IE7

.attr("checked", "checked") not working in IE7


in IE7:
<code>
$('#rb').attr("checked", "checked")
</code>
does not check a radiobutton, and
<code>
$('#rb').removeAttr("checked")
</code>
does not uncheck a radiobutton.
These code samples work fine in all the other browsers I've tried,
including IE8 and IE8 in IE7 compatibility mode. I also tried using
<code>
$('#rb').attr("checked",true);
</code>
and
</code>
<code>
$('#rb').attr("checked",false);
</code>
but these also do not work in IE7. Any help?