Quiz scoring

// http://www.gravityhelp.com/forums/topic/mathematics-to-gravity-forms
add_action('gform_pre_submission', 'ch_total_quiz_values');
function ch_total_quiz_values ($form) {
    // change the number 20 here to your form ID
    // if this is not form 20, don't do any processing
    if($form['id'] != 20)
        return $form;

    // otherwise ...
    $score = 0;
    // my radio button inputs are numbered 1 to 20.  Change the beginning
    // and ending number in this loop to match your actual input numbers
    for($i=1; $i<=20; $i++) {
        // add the value of the $_POST value for input 1 to input 20
        $input  = 'input_' . $i;
        $score += rgpost($input);
    }
    // update the hidden 'Score' field with our calculated score
    $_POST['input_25'] = $score;
    switch($score) {
        // my "admin only" Rating field to hold the display message based on the score in input_24
        case 0:
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
            $_POST['input_24'] = '5 or fewer correct answers: You\'re a complacent leader who ignores changes in the environment.';
            break;
        case 6:
        case 7:
        case 8:
        case 9:
        case 10:
            $_POST['input_24'] = '6 to 10 correct answers: You\'re a leader who is comfortable with the status quo.';
            break;
        case 11:
        case 12:
        case 13:
        case 14:
        case 15:
            $_POST['input_24'] = '11 to 15 correct answers: You\'re a take charge leader who creates their own future.';
            break;
        default:
            $_POST['input_24'] = 'More than 15 correct answers: They\'re ready to produce a reality show about you: "Most Admired Leader"';
    }
    return $form;
}