double sumOfSquaresOfDeltas = 0.0;
        double c = 0.0;
        for (double value : values) {
          double delta = value - mean;
          double deltaSquared = delta * delta;
          double y = deltaSquared - c;
          double t = sumOfSquaresOfDeltas + deltaSquared;
          c = (t - sumOfSquaresOfDeltas) - y;
          sumOfSquaresOfDeltas = t;
        }