Question

How to calculate the mean and the standard deviation of an array of floating-point values in C#

Answer 1

using System;

class StatsCalculator
{
    static void Main()
    {
        double[] numbers = { 3.4, 1.8, 4.3, 5.0, 6.2 };

        double mean = CalculateMean(numbers);
        double stddev = CalculateStandardDeviation(numbers, mean);

        Console.WriteLine($"Mean: {mean:F2}");
        Console.WriteLine($"Standard Deviation: {stddev:F2}");
    }

    static double CalculateMean(double[] data) {
        if (data.Length == 0) return 0.0;

        double sum = 0.0;
        foreach (double value in data) {
            sum += value;
        }
        
        return sum / data.Length;
    }

    static double CalculateStandardDeviation(double[] data, double mean) {
        if (data.Length < 2) return 0.0;

        double sumOfSquaredDifferences = 0.0;
        foreach (double value in data) {
            double diff = value - mean;
            sumOfSquaredDifferences += diff * diff;
        }

        double variance = sumOfSquaredDifferences / (data.Length - 1); 
        
        return Math.Sqrt(variance);
    }
}



/*
run:

Mean: 4.14
Standard Deviation: 1.66

*/

 

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