public static double StandardDeviation(IEnumerable‹double› sequence) { var computation = (Count: 0, Sum: 0.0, SumOfSquares: 0.0); foreach (var item in sequence) { computation.Count++; computation.Sum += item; computation.SumOfSquares += item * item; } var variance = computation.SumOfSquares - computation.Sum * computation.Sum / computation.Count; return Math.Sqrt(variance / computation.Count); }