Radio Validation

I am trying to figure out a simple radio validation using a simple function.

Basically there are 12 sets of radio buttons, 4 buttons in each set. Sets are names q1, q2, q3 ... q12.

I want to loop through each set without having to write an independent function for each. My script works for a single function, but I get an error when I try to loop through each function.

I want a corresponding error variable set for each set that is not checked, and this is what's causing the problem.

Ex: if set q1 has not been pressed, I want error1 to = 1. For set 2, error2 = 1, etc.

var total = 12;

for (i = 1; i <= total; i++){

// set var radio_choice to false
var radio_choice = false;

for (counter = 0; counter < survey.q[i].length; counter++){

if (survey.q[i][counter].checked) radio_choice = true; 
}
if (!radio_choice){
var error[i] = 1; 
}

}

Code (markup):

 

What does the survey variable refer to?