Program: Calculate Standard Deviation in Java

public class PopulationStandardDeviation {
    public static double calculatePopulationStandardDeviation(double[] population) {
        if (population.length < 1) {
            throw new IllegalArgumentException("At least one number is required to calculate population standard deviation.");
        }

        // Step 1: Calculate the mean
        double sum = 0;
        for (double num : population) {
            sum += num;
        }
        double mean = sum / population.length;

        // Step 2: Calculate the sum of squared differences
        double sumSquaredDiff = 0;
        for (double num : population) {
            sumSquaredDiff += Math.pow(num - mean, 2);
        }

        // Step 3: Calculate the population variance
        double populationVariance = sumSquaredDiff / population.length;

        // Step 4: Calculate the population standard deviation
        return Math.sqrt(populationVariance);
    }

    public static void main(String[] args) {
        double[] population = {2, 4, 4, 4, 5, 5, 7, 9};
        double popStdDev = calculatePopulationStandardDeviation(population);
        System.out.printf("The population standard deviation is: %.2f", popStdDev);
    }
}