sketch of some karma calculation functions

import math

def get_confidence_interval(p, n, alpha=0.5):
    assert p >= 0 and p <= 1
    assert alpha > 0 and alpha < 1

    z = pnorm(1-alpha/2)

    return (p + (math.pow(z, 2)/(2*n)) - z * math.sqrt((p * (1 - p) + (math.pow(z, 2)/(4*n)))/n))


pnorm_table = [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]

def pnorm(qn):
    assert qn >= 0.0 and qn <= 1.0, "Error : qn <= 0 or qn >= 1  in pnorm()!\n"

    if(qn == 0.5):
        return 0.0

    w1 = qn
    if(qn > 0.5):
        w1 = 1.0 - w1

    w3 = 0 - math.log(4.0 * w1 * (1.0 - w1))
    w1 = pnorm_table[0]
    for i in range(1, 11):
      w1 += pnorm_table[i] * math.pow(w3, i);

    if(qn > 0.5):
        return math.sqrt(w1 * w3)

    return 0 - math.sqrt(w1 * w3)