[jQuery] toggle radio sets with a checkbox

[phpLord]

Hi;
I have been trying to enable/disable 4 group of radio sets by checking 
and unchecking a checkbox.

My function is like below, what's wrong with that, or any suggestions 
for this?

var points=new Array("creativity","composition","aesthetic","technic");
       for (j in points )
       {
           var x=document.getElementsByName(points[j]);
           for (i=0;i<=x.length-1;i++ )
           {
               x[i].disabled = $("#nopoint").checked ? true : false;

           }           
       }   

Note: As you see,I am newbie in jQuery, ready for any type for 
suggestions, thanks...