jQuery check a radio button

// jQuery version 1.6 or above use:  
$("#myRadioID").prop("checked", true);
 
//jQuery versions below 1.6 use:
$("#myRadioID").attr('checked', 'checked');$("checkbox").is(":checked")$("input:radio[name='thename']").each(function(i) {
       this.checked = false;
});//<input type="radio" name="book_condition" value="3" >
$("input:radio[value='3'][name='book_condition']").prop('checked',true);