function isArrayOfNumbers(arg) {
        var result = false;
        if(Array.isArray(arg)) {
            result = (arg.filter(function(item){return !isNumeric(item);}).length === 0);
        }
        return result;
    }
Returns true if the arg is an array of numbers
@param {*} arg - the item to test
@returns {boolean} True if arg is an array of numbers