statisticalOutLierAnalysis.java discover numbers outside standard deviation

statisticalOutLierAnalysis.java

public static List<Double> statisticalOutLierAnalysis(List<Double> allNumbers) {
        if (allNumbers.isEmpty()) {
            return null;
        }

        List<Double> normalNumbers = new ArrayList<Double>();
        List<Double> outLierNumbers = new ArrayList<Double>();

        Double sum = 0D;
        for (Double number : allNumbers) {
            sum += number;
        }

        double avg = sum / allNumbers.size();

        sum = 0D;
        for (Double number : allNumbers) {
            sum += Math.pow(number - avg, 2);
        }

        double standardDeviation = sum / allNumbers.size();

        for (Double number : allNumbers) {
            if ((Math.abs(number - avg)) > (2 * standardDeviation)) {
                outLierNumbers.add(number);
            } else {
                normalNumbers.add(number);
            }
        }

        return normalNumbers;
    }

Hello friend, you forgot to get the square root of sum / size at line 21.