Variance calculation for Data Mining course

VarianceCalculation.java

public class VarianceCalculation {
    public static void main(String[] args) {
        double[] example = {30, 36, 47, 50, 52, 52, 56, 60, 63, 70, 70, 110};
        System.out.println("Mean: " + calculateMean(example));
        System.out.println("Variance: " + calculateVariance(example));
    }

    public static double calculateVariance(double[] nums) {
        double mean = calculateMean(nums);
        double sum = 0;
        for (double num : nums) {
            sum += Math.pow(num - mean, 2);
        }
        return sum / nums.length;
    }

    public static double calculateMean(double[] nums) {
        double sum = 0;
        for (double num : nums) {
            sum += num;
        }
        return sum / nums.length;
    }
}