Mean is average of a given set of data. Let us consider below example 2, 4, 4, 4, 5, 5, 7, 9 the mean (average) of a given set of data is 5

**Fact about Mean :**

- The mean (or average) is the most popular and well known measure of central tendency.
- It can be used with both discrete and continuous data, although its use is most often with continuous data.
- There are other types of means.Geometric mean, Harmonic mean and Arithmetic mean.
- Mean is the only measure of central tendency where the sum of the deviations of each value from the mean is always zero.

**Formula of mean of ungrouped data :****Formula of mean of grouped data :**

**How to find Mean ?**

Given *n* size unsorted array, find its mean.

Mean of an array =(sum of all elements) / (number of elements)Since the array is not sorted here, we sort the array first, then apply above formula.

**Examples:**

Input :{1, 3, 4, 2, 6, 5, 8, 7}Output :Mean = 4.5 Sum of the elements is 1 + 3 + 4 + 2 + 6 + 5 + 8 + 7 = 36 Mean = 36/8 = 4.5Input :{4, 4, 4, 4, 4}Output :Mean = 4

Below is the code implementation:

## C++

`// CPP program to find mean` `#include <bits/stdc++.h>` `using` `namespace` `std;` ` ` `// Function for calculating mean` `double` `findMean(` `int` `a[], ` `int` `n)` `{` ` ` `int` `sum = 0;` ` ` `for` `(` `int` `i = 0; i < n; i++)` ` ` `sum += a[i];` ` ` ` ` `return` `(` `double` `)sum / (` `double` `)n;` `}` ` ` `// Driver program` `int` `main()` `{` ` ` `int` `a[] = { 1, 3, 4, 2, 7, 5, 8, 6 };` ` ` `int` `n = ` `sizeof` `(a) / ` `sizeof` `(a[0]);` ` ` `cout << ` `"Mean = "` `<< findMean(a, n) << endl;` ` ` `return` `0;` `}` |

## Java

`// Java program to find mean` `import` `java.util.*;` ` ` `class` `GFG {` ` ` ` ` `// Function for calculating mean` ` ` `public` `static` `double` `findMean(` `int` `a[], ` `int` `n)` ` ` `{` ` ` `int` `sum = ` `0` `;` ` ` `for` `(` `int` `i = ` `0` `; i < n; i++)` ` ` `sum += a[i];` ` ` ` ` `return` `(` `double` `)sum / (` `double` `)n;` ` ` `}` ` ` ` ` `// Driver program` ` ` `public` `static` `void` `main(String args[])` ` ` `{` ` ` `int` `a[] = { ` `1` `, ` `3` `, ` `4` `, ` `2` `, ` `7` `, ` `5` `, ` `8` `, ` `6` `};` ` ` `int` `n = a.length;` ` ` `System.out.println(` `"Mean = "` `+ findMean(a, n));` ` ` `}` `}` |

## Python3

`# Python3 program to find mean ` ` ` `# Function for calculating mean` `def` `findMean(a, n):` ` ` ` ` `sum` `=` `0` ` ` `for` `i ` `in` `range` `( ` `0` `, n):` ` ` `sum` `+` `=` `a[i]` ` ` ` ` `return` `float` `(` `sum` `/` `n)` ` ` `# Driver program` `a ` `=` `[ ` `1` `, ` `3` `, ` `4` `, ` `2` `, ` `7` `, ` `5` `, ` `8` `, ` `6` `]` `n ` `=` `len` `(a)` `print` `(` `"Mean ="` `, findMean(a, n))` |

## C#

`// C# program to find mean` `using` `System;` ` ` `class` `GFG {` ` ` `// Function for` ` ` `// calculating mean` ` ` `public` `static` `double` `findMean(` `int` `[] a, ` `int` `n)` ` ` `{` ` ` `int` `sum = 0;` ` ` `for` `(` `int` `i = 0; i < n; i++)` ` ` `sum += a[i];` ` ` ` ` `return` `(` `double` `)sum / (` `double` `)n;` ` ` `}` ` ` ` ` `// Driver Code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `[] a = { 1, 3, 4, 2,` ` ` `7, 5, 8, 6 };` ` ` `int` `n = a.Length;` ` ` `Console.Write(` `"Mean = "` `+ findMean(a, n) + ` `"\n"` `);` ` ` `}` `}` |

## PHP

`<?php ` `// PHP program to find mean ` ` ` `// Function for calculating mean` `function` `findMean(&` `$a` `, ` `$n` `)` `{` ` ` `$sum` `= 0;` ` ` `for` `(` `$i` `= 0; ` `$i` `< ` `$n` `; ` `$i` `++) ` ` ` `$sum` `+= ` `$a` `[` `$i` `];` ` ` ` ` `return` `(double)` `$sum` `/ ` ` ` `(double)` `$n` `;` `}` ` ` `// Driver Code` `$a` `= ` `array` `(1, 3, 4, 2, ` ` ` `7, 5, 8, 6);` `$n` `= sizeof(` `$a` `);` `echo` `"Mean = "` `. ` ` ` `findMean(` `$a` `, ` `$n` `).` `"\n"` `; ` `?>` |

**Output:**

Mean = 4.5

Time Complexity to find mean = O(n)

**Basic Program related to Mean**

- Find mean of subarray means in a given array
- Mean of array using recursion
- Find the mean vector of a Matrix
- Mean of range in array
- Mean and Median of a matrix

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