# Program for Mean Absolute Deviation

Given an array of size n, find mean absolute deviation.
Prerequisite : Mean, Variance and Standard Deviation

Examples:

```Input : arr[] = {10, 15, 15, 17, 18, 21}
Output : 2.66667

Input : arr[] = {23.54, 56, 34.56, 67, 45.34,
56.78, 78, 21}
Output : 16.6675
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Mean absolute deviation or Average absolute deviation of data set is the average of absolute difference from mean or central point.Mean absolute deviation can be calculated by using the method given below.
Let arr[n] be an array of size n and the task is to find mean absolute deviation.
Mean absolute deviation = (abs(arr[0] – mean) + abs(arr[1] – mean) + . . . + abs(arr[n-1] – mean) / n;
where i = 0, 1, 2, . . . n-1 and “abs” is absolute difference.
mean = (arr[0] + arr[1] + arr[2] + . . . + arr[n-1]) / n;

## C++

 `// C++ Program to find mean absolute ` `// deviation of given array. ` `#include ` `using` `namespace` `std; ` ` `  `// Function to find mean ` `// of the array elements. ` `float` `Mean(``float` `arr[], ``int` `n) ` `{    ` `    ``// Calculate sum of all elements. ` `    ``float` `sum = 0; ` `    ``for` `(``int` `i = 0; i < n; i++) ` `        ``sum = sum + arr[i]; ` `    ``return` `sum / n; ` `} ` ` `  `// Function to find mean absolute ` `// deviation of given elements. ` `float` `meanAbsoluteDeviation(``float` `arr[], ``int` `n) ` `{    ` `    ``// Calculate the sum of absolute ` `    ``// deviation about mean. ` `    ``float` `absSum = 0; ` `    ``for` `(``int` `i = 0; i < n; i++) ` `        ``absSum = absSum + ``abs``(arr[i] - Mean(arr, n)); ` ` `  `    ``// Return mean absolute deviation about mean. ` `    ``return` `absSum / n; ` `} ` ` `  `// Driver function. ` `int` `main() ` `{ ` `    ``float` `arr[] = { 10, 15, 15, 17, 18, 21 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]); ` `    ``cout << meanAbsoluteDeviation(arr, n); ` `    ``return` `0; ` `} `

## Java

 `// java Program to find mean absolute ` `// deviation of given array ` `import` `java.io.*; ` ` `  `class` `GFG { ` `         `  `    ``// Function to find mean ` `    ``// of the array elements. ` `    ``static` `float` `Mean(``float` `arr[], ``int` `n) ` `    ``{  ` `        ``// Calculate sum of all elements. ` `        ``float` `sum = ``0``; ` `         `  `        ``for` `(``int` `i = ``0``; i < n; i++) ` `            ``sum = sum + arr[i]; ` `         `  `        ``return` `sum / n; ` `    ``} ` `     `  `    ``// Function to find mean absolute ` `    ``// deviation of given elements. ` `    ``static` `float` `meanAbsDevtion(``float` `arr[], ` `                                       ``int` `n) ` `    ``{  ` `        ``// Calculate the sum of absolute ` `        ``// deviation about mean. ` `        ``float` `absSum = ``0``; ` `         `  `        ``for` `(``int` `i = ``0``; i < n; i++) ` `            ``absSum = absSum + Math.abs(arr[i] ` `                                ``- Mean(arr, n)); ` `     `  `        ``// Return mean absolute  ` `        ``// deviation about mean. ` `        ``return` `absSum / n; ` `    ``} ` `     `  `        ``// Driver function. ` `        ``public` `static` `void` `main (String[] args) { ` `         `  `        ``float` `arr[] = { ``10``, ``15``, ``15``, ``17``, ``18``, ``21` `}; ` `        ``int` `n = arr.length; ` `         `  `            ``System.out.println(meanAbsDevtion(arr, n)); ` `        ``} ` `} ` ` `  ` `  `// This code is contributed by vt_m `

## Python3

 `# Python 3 Program to find ` `# mean absolute deviation  ` `# of given array. ` ` `  `# Function to find mean ` `# of the array elements. ` `def` `Mean(arr, n) : ` ` `  `    ``# Calculate sum of all ` `    ``# elements. ` `    ``sm ``=` `0` `     `  `    ``for` `i ``in` `range``(``0``, n) : ` `        ``sm ``=` `sm ``+` `arr[i] ` `    ``return` `sm ``/``/` `n ` `     `  `# Function to find mean  ` `# absolute deviation of  ` `# given elements. ` `def` `meanAbsoluteDeviation(arr, n) : ` `     `  `    ``# Calculate the sum of  ` `    ``# absolute deviation  ` `    ``# about mean. ` `    ``absSum ``=` `0` `    ``for` `i ``in` `range``(``0``, n ): ` `        ``absSum ``=` `absSum ``+` `abs``(arr[i] ``-` `                         ``Mean(arr, n)) ` ` `  `    ``# Return mean absolute  ` `    ``# deviation about mean. ` `    ``return` `absSum ``/` `n ` ` `  `# Driver function. ` `arr ``=` `[ ``10``, ``15``, ``15``, ``17``, ``18``, ``21` `] ` `n ``=` `len``(arr) ` ` `  `print``(meanAbsoluteDeviation(arr, n)) ` ` `  `# This code is contributed by Nikita Tiwari. `

## C#

 `// C# Program to find mean absolute ` `// deviation of given array ` `using` `System; ` ` `  `class` `GFG { ` `         `  `    ``// Function to find mean ` `    ``// of the array elements. ` `    ``static` `float` `Mean(``float` `[]arr, ``int` `n) ` `    ``{  ` `        ``// Calculate sum of all elements. ` `        ``float` `sum = 0; ` `         `  `        ``for` `(``int` `i = 0; i < n; i++) ` `            ``sum = sum + arr[i]; ` `         `  `        ``return` `sum / n; ` `    ``} ` `     `  `    ``// Function to find mean absolute ` `    ``// deviation of given elements. ` `    ``static` `float` `meanAbsDevtion(``float` `[]arr, ` `                                    ``int` `n) ` `    ``{  ` `        ``// Calculate the sum of absolute ` `        ``// deviation about mean. ` `        ``float` `absSum = 0; ` `         `  `        ``for` `(``int` `i = 0; i < n; i++) ` `            ``absSum = absSum + Math.Abs(arr[i] ` `                                ``- Mean(arr, n)); ` `     `  `        ``// Return mean absolute  ` `        ``// deviation about mean. ` `        ``return` `absSum / n; ` `    ``} ` `     `  `        ``// Driver function. ` `        ``public` `static` `void` `Main ()  ` `        ``{ ` `             `  `            ``float` `[]arr = { 10, 15, 15, 17, 18, 21 }; ` `            ``int` `n = arr.Length; ` `         `  `            ``Console.WriteLine(meanAbsDevtion(arr, n)); ` `        ``} ` `} ` ` `  ` `  `// This code is contributed by vt_m `

## PHP

 ` `

Output:

```2.66667
```

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