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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.

Example

Input 1:

4

5 6 7 8

Output 1:

1.12

Explanation:

(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(System.in);
		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
		sum=0;
		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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