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/** * The [Harmonic Mean](https://en.wikipedia.org/wiki/Harmonic_mean) is * a mean function typically used to find the average of rates. * This mean is calculated by taking the reciprocal of the arithmetic mean * of the reciprocals of the input numbers. * * This is a [measure of central tendency](https://en.wikipedia.org/wiki/Central_tendency): * a method of finding a typical or central value of a set of numbers. * * This runs in `O(n)`, linear time, with respect to the length of the array. * * @param {Array<number>} x sample of one or more data points * @returns {number} harmonic mean * @throws {Error} if x is empty * @throws {Error} if x contains a negative number * @example * harmonicMean([2, 3]).toFixed(2) // => '2.40' */function harmonicMean(x) {    if (x.length === 0) {        throw new Error("harmonicMean requires at least one data point");    }
    let reciprocalSum = 0;
    for (let i = 0; i < x.length; i++) {        // the harmonic mean is only valid for positive numbers        if (x[i] <= 0) {            throw new Error(                "harmonicMean requires only positive numbers as input"            );        }
        reciprocalSum += 1 / x[i];    }
    // divide n by the reciprocal sum    return x.length / reciprocalSum;}
export default harmonicMean;