# set_bin_prior: Construction of a prior distribution for a binomial... In revdbayes: Ratio-of-Uniforms Sampling for Bayesian Extreme Value Analysis

## Description

Constructs a prior distribution for use as the argument `bin_prior` in `rpost` or in `binpost`. The user can choose from a list of in-built priors.

## Usage

 `1` ```set_bin_prior(prior = c("jeffreys", "laplace", "haldane", "beta", "mdi"), ...) ```

## Arguments

 `prior` A character string giving the name of the prior for p. See Details for a list of the priors available. `...` Further arguments to be passed to an in-built prior function. This is only relevant if `model = "beta"`, when `ab` can be passed. See Details.

## Details

Binomial priors. The names of the binomial priors set using `bin_prior` are:

• `"jeffreys"`: the Jeffreys beta(1/2, 1/2) prior.

• `"laplace"`: the Bayes-Laplace beta(1, 1) prior.

• `"haldane"`: the Haldane beta(0, 0) prior.

• `"beta"`: a beta(α, β) prior. The argument `ab` is a vector containing `c`(α, β). The default is `ab = c(1, 1)`.

• `"mdi"`: the MDI prior π(p) = 1.6186 p^p (1-p)^(1-p), 0 < p < 1.

Apart from the MDI prior these are all beta distributions.

## Value

A list of class `"binprior"`. The first component is the name of the input prior. Apart from the MDI prior this will be "beta", in which case the other component of the list is a vector of length two giving the corresponding values of the beta parameters.

`binpost` for sampling from a binomial posterior distribution.
 `1` ```bp <- set_bin_prior(prior = "jeffreys") ```