social_learning.DiversityAnalyzer.Variance C# (CSharp) Method

        public static double Variance(IEnumerable<double> data)
        {
            if (data.Count() < 2)
                return 0;

            double avg = data.Average();
            double numerator = 0;
            foreach (double d in data)
                numerator += (d - avg) * (d - avg);

            double variance = numerator / (double)(data.Count() - 1);

            return variance;
        }
    }