Override the function.

Finalize.cs

public override string Finalize()
    {
 
//Calculating the summary statistics
       sum = rowvalue.Sum(); 
       min = rowvalue.Min();
       max = rowvalue.Max();
       count = rowvalue.Count();
       mean=rowvalue.Average();
       range=max-min;
       cumReciprocal = rowvalue.Sum(x=>1.0/x);
       HarmonicMean = rowvalue.Count()/cumReciprocal;
       GeometricMean= Math.Exp(rowvalue.Average(x=>Math.Log(x)));
       SumOfError=rowvalue.Sum(x=>Math.Abs(x-mean));
       SumOfErrorSquare=rowvalue.Sum(x=>Math.Pow(Math.Abs(x-mean),2));
       Variance=SumOfErrorSquare/((double)count-1);
       StdDev=Math.Sqrt(Variance);
       SkewCum=rowvalue.Sum(x=>Math.Pow((x-mean)/StdDev,3));
       m4=rowvalue.Sum(x=>Math.Pow((x-mean)/StdDev,4));
       Skewness=((count)/((count-1)*(count-2)))*SkewCum;
       Kurtosis=((((count + 1) * count)/((count - 1)*(count - 2)*(count - 3)))*(m4))-(3*Math.Pow(count-1,2))/((count-2) * (count-3));
 
//Sorted List
   
     double[] Sorted_List = rowvalue.OrderBy(x=>x).ToArray();
   
   
    Func<double[], double, double> percentileCal = (double[] sortedData, double p) => {
        // algo derived from Aczel pg 15 bottom
        if (p >= 100.0d) return sortedData[sortedData.Length - 1];
 
        double position = (double)(sortedData.Length + 1) * p / 100.0;
        double leftNumber = 0.0d, rightNumber = 0.0d;
 
        double n = p / 100.0d * (sortedData.Length - 1) + 1.0d;
 
        if (position >= 1)
        {
            leftNumber = sortedData[(int)System.Math.Floor(n) - 1];
            rightNumber = sortedData[(int)System.Math.Floor(n)];
        }
        else
        {
            leftNumber = sortedData[0]; // first data
            rightNumber = sortedData[1]; // first data
        }
 
        if (leftNumber == rightNumber)
            return leftNumber;
        else
        {
            double part = n - System.Math.Floor(n);
            return leftNumber + part * (rightNumber - leftNumber);
        }
    };
 
    FirstQuartile = percentileCal(Sorted_List, 25);
    ThirdQuartile = percentileCal(Sorted_List, 75);
    Median = percentileCal(Sorted_List, 50);
    IQR = percentileCal(Sorted_List, 75) - percentileCal(Sorted_List, 25);
  
 
 
    string outputString = FirstQuartile.ToString()+","+Kurtosis.ToString()+","+Skewness.ToString()+","+SkewCum.ToString()+","+StdDev.ToString()+","+Variance.ToString()+","+SumOfErrorSquare.ToString()+","+SumOfError.ToString()+","+sum.ToString()+","+min.ToString()+","+max.ToString()+","+ count.ToString()+","+ mean.ToString()+","+range.ToString()+","+GeometricMean.ToString()+","+HarmonicMean.ToString(); //note that the output will be string
    return outputString.ToString();
 
   
    }