[JavaScript][Example] get simple mean from a list of numbers

This post mark down the logic using javaSrcipt execute simply mean calaulation.
source samples are with string data type and separated by comma.
using this formula :

<script>
const ROUND_TO_FIXED = 2;
function _stringToList(string){
    return string.split(",");
}
function _roundToFixed(num){
    return Number(parseFloat(num).toFixed(ROUND_TO_FIXED));
}
function getSampleMean(string){
    var sourceList = _stringToList(string),
        sum        = 0;
    for(var i in sourceList){
        sum += parseFloat(sourceList[i]);
    }
    return _roundToFixed(sum / sourceList.length);
}
var source = "1,2,3,5,1,2,6"
console.log(getSampleMean(source));
</script>

Result:
2.86

Reference:
https://en.wikipedia.org/wiki/Mean
https://www.w3schools.com/Js/js_json_parse.asp
https://stackoverflow.com/questions/9907419/how-to-get-a-key-in-a-javascript-object-by-its-value