calculate standard deviation (#12963)

Co-authored-by: tienvn4 <tienvn4@ghtk.co>

core-java-modules/core-java-lang-math-3/src/main/java/com/baeldung/math/standarddeviation/StandardDeviation.java

@@ -0,0 +1,35 @@
+package com.baeldung.math.standarddeviation;
+
+import java.util.Arrays;
+
+public class StandardDeviation {
+
+    public static double calculateStandardDeviation(double[] array) {
+
+        // get the sum of array
+        double sum = 0.0;
+        for (double i : array) {
+            sum += i;
+        }
+
+        // get the mean of array
+        int length = array.length;
+        double mean = sum / length;
+
+        // calculate the standard deviation
+        double standardDeviation = 0.0;
+        for (double num : array) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation / length);
+    }
+
+    public static void main(String[] args) {
+        double[] array = {25, 5, 45, 68, 61, 46, 24, 95};
+        System.out.println("List of elements: " + Arrays.toString(array));
+
+        double standardDeviation = calculateStandardDeviation(array);
+        System.out.format("Standard Deviation = %.6f", standardDeviation);
+    }
+}