在质量标准中使用平均函数

Qualtrics.SurveyEngine.addOnload(function()
{
    var a = "${e://Fields/a}"
    var b = "${e://Fields/b}"
    var c = "${e://Fields/c}"

    a= parseFloat(a)
    b= parseFloat(b)
    c= parseFloat(c)
    var all_values= [a, b, c];
    function isnonzero(value) {
        return value != 0;
    }   
    var filter_it;
    filter_it = all_values.filter(isnonzero);
    function avg(filter_it){
        var sum = 0;
        for (var i = 0; i < filter_it.length; i++) {
            sum += parseFloat(filter_it[i])
        }
        return sum / filter_it.length;
    }
    var average = avg(filter_it);
    Qualtrics.SurveyEngine.setEmbeddedData("total",average);

});