To uncheck radio button, you may use .removeAttr or .attr
$("input:radio").attr("checked", false);
//with id
$("input#id_of_button").attr("checked", false);
//or
$("#id_of_button").attr("checked", false);
Or using .removeAttr
$("input:radio").removeAttr("checked");
//with id
$("input#id_of_button").removeAttr("checked");
//or
$("#id_of_button").removeAttr("checked");
To checked a radio button, view this post
What do you think?