Mean - GeeksforGeeks

11 Dec, 2018
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.
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 = 4.5

Input  : {4, 4, 4, 4, 4}
Output : Mean = 4
Below is the code implementation:
C++
Java
Python3
C#
PHP
// CPP program to find mean#include <bits/stdc++.h>using namespace std;  // Function for calculating meandouble findMean(int a[], int n){    int sum = 0;    for (int i = 0; i < n; i++)        sum += a[i];      return (double)sum / (double)n;}  // Driver programint 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 program to find meanimport 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 program to find mean   # Function for calculating meandef findMean(a, n):      sum = 0    for i in range( 0, n):        sum += a[i]          return float(sum / n)  # Driver programa = [ 1, 3, 4, 2, 7, 5, 8, 6 ]n = len(a)print("Mean =", findMean(a, n))
// C# program to find meanusing 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 program to find mean   // Function for calculating meanfunction 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"; ?>
Mean = 4.5
Time Complexity to find mean = O(n)
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