Function to provide Wilson lower bound score for given positive and total ratings

wilson_score.py

import math
import scipy.stats as st

def wilson_lower_bound(pos, n, confidence=0.95):
    """
    Function to provide lower bound of wilson score
    :param pos: No of positive ratings
    :param n: Total number of ratings
    :param confidence: Confidence interval, by default is 95 %
    :return: Wilson Lower bound score
    """
    if n == 0:
        return 0
    z = st.norm.ppf(1 - (1 - confidence) / 2)
    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)