weighted-mean/index.js

Calculates the weighted mean of an array of numbers

'use strict';

function weightedMean(weightedValues) {
    var totalWeight = weightedValues.reduce(function (sum, weightedValue) {
        return sum + weightedValue[1];
    }, 0);

    return weightedValues.reduce(function (mean, weightedValue) {
        return mean + weightedValue[0] * weightedValue[1] / totalWeight;
    }, 0);
}

module.exports = weightedMean;