es-next-tools/dist/math/statistics.js

A comprehensive utility library for JavaScript and TypeScript that provides a wide range of functions for common programming tasks, including mathematical operations, date manipulations, array and object handling, string utilities, and more.

/**
 * Calculates the variance of a set of numbers.
 * @param {number[]} numbers - The array of numbers to calculate variance for.
 * @returns {number} The variance of the numbers.
 * @example
 * console.log(variance([1, 2, 3, 4, 5])); // 2
 * console.log(variance([10, 10, 10])); // 0
 */
export function variance(numbers) {
    if (numbers.length === 0)
        return 0;
    const mean = numbers.reduce((sum, num) => sum + num, 0) / numbers.length;
    const squareDiffs = numbers.map(num => Math.pow(num - mean, 2));
    return squareDiffs.reduce((sum, diff) => sum + diff, 0) / numbers.length;
}
/**
 * Calculates the standard deviation of a set of numbers.
 * @param {number[]} numbers - The array of numbers to calculate standard deviation for.
 * @returns {number} The standard deviation of the numbers.
 * @example
 * console.log(standardDeviation([2, 4, 4, 4, 5, 5, 7, 9])); // 2
 * console.log(standardDeviation([10, 10, 10])); // 0
 */
export function standardDeviation(numbers) {
    return Math.sqrt(variance(numbers));
}