public double GetMoment(int k, int index1, int index2, int row)
{
EnsureNotEmpty($"Can not calculate momentum. Series {this.name} is empty.");
EnsureIndexInRange(index1, index2);
double m = k != 1 ? GetMean(index1, index2, row) : 0;
var count = index2 - index1 + 1;
return Enumerable.Range(index1, count).Sum(i => Math.Pow(this[i, row] - m, k)) / count;
}