import math


def binomial_coefficient(k, i):
    """ Computes the binomial coefficient (denoted by *k choose i*).

    Please see the following website for details: http://mathworld.wolfram.com/BinomialCoefficient.html

    :param k: size of the set of distinct elements
    :type k: int
    :param i: size of the subsets
    :type i: int
    :return: combination of *k* and *i*
    :rtype: float
    """
    k_fact = math.factorial(k)
    i_fact = math.factorial(i)
    k_i_fact = math.factorial(k - i)
    return float(k_fact / (k_i_fact * i_fact))