# Program to find covariance

Given a two set of random variable, find Covariance. Covariance is a measure of how much two random variables vary together. It’s similar to variance, but where variance tells you how a single variable varies, covariance tells you how two variables vary together. Covariance can be calculated by using the formula Where x’ and y’ are the means of two given sets.

Examples:

Input : arr1[] = {65.21, 64.75, 65.26, 65.76, 65.96}
arr2[] = {67.25, 66.39, 66.12, 65.70, 66.64}
Output : -0.0580511

Input : arr1[] = {5, 20, 40, 80, 100}
arr2[] = {10, 24, 33, 54, 10}
Output : 187.75


## C++

 // CPP Program to find  // covariance of two set.  #include  using namespace std;     // Function to find mean.  float mean(float arr[], int n)  {      float sum = 0;      for(int i = 0; i < n; i++)          sum = sum + arr[i];      return sum / n;  }     // Function to find covariance.  float covariance(float arr1[], float arr2[], int n)  {      float sum = 0;      for(int i = 0; i < n; i++)          sum = sum + (arr1[i] - mean(arr1, n)) *                      (arr2[i] - mean(arr2, n));      return sum / (n - 1);  }     // Driver function.  int main()  {      float arr1[] = {65.21, 64.75, 65.26, 65.76, 65.96};      int n = sizeof(arr1) / sizeof(arr1);             float arr2[] = {67.25, 66.39, 66.12, 65.70, 66.64};      int m = sizeof(arr2) / sizeof(arr2);             if (m == n)          cout << covariance(arr1, arr2, m);      return 0;  }

## Java

 // Java Program to find  // covariance of two set.  import java.io.*;     class GFG {     // Function to find mean.  static float mean(float arr[], int n)  {      float sum = 0;             for(int i = 0; i < n; i++)          sum = sum + arr[i];             return sum / n;  }     // Function to find covariance.  static float covariance(float arr1[],                      float arr2[], int n)  {      float sum = 0;             for(int i = 0; i < n; i++)          sum = sum + (arr1[i] - mean(arr1, n)) *                          (arr2[i] - mean(arr2, n));      return sum / (n - 1);  }     // Driver code      public static void main (String[] args) {             float arr1[] = {65.21f, 64.75f,                 65.26f, 65.76f, 65.96f};      int n = arr1.length;             float arr2[] = {67.25f, 66.39f,                  66.12f, 65.70f, 66.64f};             int m = arr2.length;             if (m == n)             System.out.println(covariance(arr1, arr2, m));             }  }     // This code is contributed by Gitanjali.

## Python3

 # Python3 Program to find  # covariance of two set.  import math     # Function to find mean.  def mean(arr, n):             sum = 0     for i in range(0, n):          sum = sum + arr[i]             return sum / n     # Function to find covariance.  def covariance(arr1, arr2, n):         sum = 0     for i in range(0, n):          sum = (sum + (arr1[i] - mean(arr1, n)) *                       (arr2[i] - mean(arr2, n)))             return sum / (n - 1)     # Driver method  arr1 = [65.21, 64.75, 65.26, 65.76, 65.96]  n = len(arr1)     arr2 = [67.25, 66.39, 66.12, 65.70, 66.64]  m = len(arr2)     if (m == n):      print (covariance(arr1, arr2, m))     # This code is contributed by Gitanjali.

## C#

 // C# Program to find  // covariance of two set.  using System;     class GFG {         // Function to find mean.      static float mean(float []arr, int n)      {          float sum = 0;                     for(int i = 0; i < n; i++)              sum = sum + arr[i];                     return sum / n;      }             // Function to find covariance.      static float covariance(float []arr1,                          float []arr2, int n)      {          float sum = 0;                     for(int i = 0; i < n; i++)              sum = sum + (arr1[i] - mean(arr1, n)) *                              (arr2[i] - mean(arr2, n));          return sum / (n - 1);      }             // Driver code      public static void Main () {                 float []arr1 = {65.21f, 64.75f,                  65.26f, 65.76f, 65.96f};          int n = arr1.Length;                     float []arr2 = {67.25f, 66.39f,                      66.12f, 65.70f, 66.64f};                     int m = arr2.Length;                     if (m == n)                     Console.WriteLine(covariance(arr1, arr2, m));             }  }     // This code is contributed by vt_m.

## PHP

 

Output:

-0.0580511


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