/// <summary> /// Estimates the unbiased population variance from the provided samples. /// On a dataset of size N will use an N-1 normalizer (Bessel's correction). /// Returns NaN if data has less than two entries or if any entry is NaN. /// </summary> /// <param name="samples">A subset of samples, sampled from the full population.</param> public static double Variance(this IEnumerable <double> samples) { var array = samples as double[]; return(array != null ? ArrayStatistics.Variance(array) : StreamingStatistics.Variance(samples)); }