# credint: Calculate Bayesian credible intervals In emdbook: Support Functions and Data for "Ecological Models and Data"

## Description

Calculate Bayesian credible intervals based on various types of information about the posterior distribution

## Usage

 ```1 2``` ```tcredint(dist, parlist, ranges, level = 0.95, eps = 1e-05,verbose=FALSE) ncredint(pvec,npost,level=0.95,tol=0.01,verbose=FALSE) ```

## Arguments

 `dist` character string giving the name of a distribution for which "d", "q", and "p" function exist, e.g. "beta" `parlist` list of parameters to pass to distribution functions `ranges` lower, middle, and upper values to bracket lower and upper boundaries of the credible interval `level` confidence level `eps` if `ranges` is missing, set lower and upper brackets to the `eps` and `1-eps` quantiles of the distribution `tol` tolerance on credible interval `verbose` if TRUE, return detailed information on the probability cutoff and realized area of the credible interval; if FALSE, just lower and upper bounds of the credible region `...` additional arguments to `density` `pvec` numeric vector of parameter values `npost` numeric vector of posterior density values corresponding to `pvec`

## Details

`tcredint` gives credible intervals for a theoretical posterior density with defined density, cumulative density, and quantile functions; `ncredint` gives credible intervals for a numerical posterior density.

## Value

A numeric vector giving the credible interval. If `verbose=FALSE`, gives just lower and upper bounds; if `verbose=TRUE`, also gives information on the probability cutoff and realized area of the credible interval

## Note

For credible intervals from a sample (e.g. from an MCMC run), see `HPDinterval` in the `coda` package.

Ben Bolker

## Examples

 ```1 2 3 4 5``` ```tcredint("beta",list(shape1=5,shape2=10),verbose=TRUE) pvec = seq(0,1,length=100) postvec = dbeta(pvec,shape1=5,shape2=10) ncredint(pvec,postvec,verbose=TRUE) set.seed(1001) ```

### Example output

```    lower     upper         p      area
0.1145856 0.5639456 0.5771295 0.9500001
lower     upper         p      area
0.1212121 0.5555556 0.6100000 0.9471975
```

emdbook documentation built on May 2, 2019, 9:41 a.m.