Standard Deviation of an Array in Java

The square root of variance is the standard deviation. It is a gauge of how far data deviates from the mean. Get an array of Integers arr[] with size n and calculate the standard deviation of arr[].The Output should be printed in two decimal places.


Input 1:


5 6 7 8

Output 1:



(Standard Deviation is the Square root of Variance)

Try your Solution

Strongly recommended to Solve it on your own, Don't directly go to the solution given below.

public class Hello { public static void main(String args[]) { //Write your code here } }

Program or Solution


import java.util.*;

class Sd


public static void main(String args[])


//Variable and  Object Declarations

        Scanner input = new Scanner(;

int n;

float sum = 0f;

double mean, variance, sd;

//Getting size of Array & Declare Array arr[]

n = input.nextInt();

int arr[] = new int[n];

//Get n values to array arr[]

for(int i = 0; i<n; i++)


arr[i] = input.nextInt();


//Calcualte Sum and Mean

for(int i = 0; i<n; i++)


sum+= arr[i];


mean = sum/n;

//Calculate Variance for Whole Population


for(int i = 0; i<n; i++)


double diff = arr[i]-mean;

sum += Math.pow(diff,2);


variance = sum/(n);

sd = Math.sqrt(variance);

System.out.printf("%.2f", sd);



Program Explanation


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