C# from Ruby Wilson score

Question

Can anyone help me convert this to C#. It's literally hurting my brain.

http://www.evanmiller.org/how-not-to-sort-by-average-rating.html

require 'statistics2'

def ci_lower_bound(pos, n, power)
    if n == 0
        return 0
    end
    z = Statistics2.pnormaldist(1-power/2)
    phat = 1.0*pos/n
    (phat + z*z/(2*n) - z * Math.sqrt((phat*(1-phat)+z*z/(4*n))/n))/(1+z*z/n)
end

What does this mean?

Statistics2.pnormaldist(1-power/2) 

Answer 1

In case anyone is interested...

doing more googling of pnormaldist led me to this stackoverflow artice: Objective-C implementation of the Wilson Score Interval

I converted this objective-c to C# mannually and it's completely untested

public class WilsonScore
{
    private static double pnormaldist(double qn)
    {
        double[] b = { 1.570796288, 0.03706987906, -0.8364353589e-3, -0.2250947176e-3, 
                         0.6841218299e-5, 0.5824238515e-5, -0.104527497e-5, 
                         0.8360937017e-7, -0.3231081277e-8, 0.3657763036e-10, 
                         0.6936233982e-12 };

        if (qn < 0.0 || 1.0 < qn)
            return 0.0;

        if (qn == 0.5)
            return 0.0;

        double w1 = qn;
        if (qn > 0.5)
            w1 = 1.0 - w1;
        double w3 = -Math.Log(4.0 * w1 * (1.0 - w1));
        w1 = b[0];
        int i = 1;
        for (; i < 11; i++)
            w1 += b[i] * Math.Pow(w3, i);

        if (qn > 0.5)
            return Math.Sqrt(w1 * w3);
        return -Math.Sqrt(w1 * w3);
    }

    public static double ci_lower_bound(int pos, int n, double power)
    {
        if (n == 0)
            return 0.0;
        double z = pnormaldist(1 - power / 2);
        double phat = 1.0 * pos / n;
        return (phat + z * z / (2 * n) - z * Math.Sqrt((phat * (1 - phat) + z * z / (4 * n)) / n)) / (1 + z * z / n);
    }
}