Derivative of the log-beta density with respect to c where \(c = (1 - \tau)/\tau\) where \(\tau\) is the overdispersion parameter.
dlbeta_dc(x, n, xi, c)
The number of successes observed
The total number of trials observed.
The mean of the beta-binomial.
\((1 - \tau)/\tau\) where \(\tau\) is the overdispersion parameter.
A double.