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import combineMeans from "./combine_means";
/** * When combining two lists of values for which one already knows the variances, * one does not have to necessary recompute the variance of the combined lists * in linear time. They can instead use this function to compute the combined * variance by providing the variance, mean & number of values of the first list * and the variance, mean & number of values of the second list. * * @since 3.0.0 * @param {number} variance1 variance of the first list * @param {number} mean1 mean of the first list * @param {number} n1 number of items in the first list * @param {number} variance2 variance of the second list * @param {number} mean2 mean of the second list * @param {number} n2 number of items in the second list * @returns {number} the combined mean * * @example * combineVariances(14 / 3, 5, 3, 8 / 3, 4, 3); // => 47 / 12 */function combineVariances(variance1, mean1, n1, variance2, mean2, n2) {    const newMean = combineMeans(mean1, n1, mean2, n2);
    return (        (n1 * (variance1 + Math.pow(mean1 - newMean, 2)) +            n2 * (variance2 + Math.pow(mean2 - newMean, 2))) /        (n1 + n2)    );}
export default combineVariances;