}
  }

  enum VarianceAlgorithm {
    DO_NOT_COMPUTE {
      @Override
      MeanAndVariance variance(double[] values, MeanAlgorithm meanAlgorithm) {
        return new MeanAndVariance(meanAlgorithm.mean(values), 0.0);
      }
    },
    SIMPLE {
      @Override
      MeanAndVariance variance(double[] values, MeanAlgorithm meanAlgorithm) {
        double mean = meanAlgorithm.mean(values);