solbeta: Recursive resolution of beta prior calibration
Description
In the capture-recapture experiment of Chapter 5, the prior information
is represented by a prior expectation and prior confidence intervals. This
function derives the corresponding beta \(B(\alpha,\beta)\)
prior distribution by a divide-and-conquer scheme.
Usage
solbeta(a, b, c, prec = 10^(-3))
Value
alpha
first coefficient of the beta distribution
beta
second coefficient of the beta distribution
Arguments
a
lower bound of the prior 95%~confidence interval
b
upper bound of the prior 95%~confidence interval
c
mean of the prior distribution
prec
maximal precision on the beta coefficient \(\alpha\)
Details
Since the mean \(\mu\) of the beta distribution is known, there is a single free parameter
\(\alpha\) to determine, since \(\beta=\alpha(1-\mu)/\mu\). The function solbeta searches for
the corresponding value of \(\alpha\), starting with a precision of \(1\) and stopping
at the requested precision prec.