Java Program to Calculate Standard Deviation

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In this program we are going to use an individual series using arrays to calculates the Standard Deviation.

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 Program to Calculate Standard Deviation in Java

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public class Main {

    

    public static double standard_deviation(double array1[])
    {
        double sum = 0.0, standard_Deviation = 0.0;
        int len = array1.length;

        for(double num : array1) {
            sum += num;
        }

        double mean = sum/len;

        for(double num: array1) {
            standard_Deviation += Math.pow(num - mean, 2);
        }

        return Math.sqrt(standard_Deviation/len);
    }

    static double calculate_variance(double array1[])
    {
        // Compute mean (average of elements)
        int len = array1.length;
        double sum = 0;
         
        for (int i = 0; i < len; i++)
            sum += array1[i];
        double mean = (double)sum/(double)len;
     
        // Compute sum squared differences with
        // mean.
        double square_Diff = 0;
        for (int i = 0; i < len; i++) 
            square_Diff += (array1[i] - mean) * (array1[i] - mean);
         
        return (double)square_Diff/len;
    }

      public static void main(String[] args) {
        double[] arr = { 30,35,36,40,41,42,55,60,61 };
        double Standard_Deviation = standard_deviation(arr);
        System.out.printf("Standard Deviation is = %.6f", Standard_Deviation);
        System.out.println();
        double variance =calculate_variance(arr);
        System.out.printf("Varience is = %.6f", variance);
    }

}

Output:-

Standard Deviation is = 147.322775
Varience is = 21704.000000

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