pmf
Returns the probability of exactly k successes in this beta-binomial distribution.
Computes the probability mass by exponentiating the logPmf value. Returns zero for values outside the support (k < 0 or k > trials). When trials is zero, the only possible outcome is k = 0 with probability 1.
Return
the probability of exactly k successes, in the range [0, 1].
Parameters
k
the number of successes at which to evaluate the probability.