mark-and-recapture/lib/index.js

A set of mark and recapture estimator functions based on Lincoln-Peterson/Chapman/Bayesian methods.

'use strict';
//https://en.wikipedia.org/wiki/Mark_and_recapture

Object.defineProperty(exports, "__esModule", {
  value: true
});
var estimate = function estimate(capInital) {
  return function (capCurrent) {
    return function (capIntersection) {
      //https://en.wikipedia.org/wiki/Lincoln_index
      var lincolnIndex = Math.trunc(capInital * capCurrent / capIntersection);
      //https://en.wikipedia.org/wiki/Lincoln_index
      var chapmanIndex = Math.trunc((capInital + 1) * (capCurrent + 1) / (capIntersection + 1) - 1);
      //https://en.wikipedia.org/wiki/Mark_and_recapture#Bayesian_estimate
      var basyesianEstimateMean = Math.trunc((capInital - 1) * (capCurrent - 1) / (capIntersection - 2));
      var basyesianEstimateStandardDeviation = Math.sqrt((capCurrent - 1) * (capInital - 1) * (capCurrent - capIntersection + 1) * (capInital - capIntersection + 1) / ((capIntersection - 2) * (capIntersection - 2) * (capIntersection - 3)));

      return {
        lincolnIndex: lincolnIndex,
        chapmanIndex: chapmanIndex,
        basyesianEstimate: basyesianEstimateMean,
        basyesianEstimateStandardDeviation: basyesianEstimateStandardDeviation
      };
    };
  };
};

exports.estimate = estimate;