Single-Parameter Models

In this chapter, we introduce the use of R in summarizing the posterior distributions for several single-parameter models. We begin by describing Bayesian inference for a variance for a normal population and inference for a Poisson mean when informative prior information is available. For both problems, summarization of the posterior distribution is facilitated by the use of R functions to compute and simulate distributions from the exponential family. In Bayesian analyses, one may have limited beliefs about a parameter and there may be several priors that provide suitable matches to these beliefs. In estimating a normal mean, we illustrate the use of two distinct priors in modeling beliefs, and show that inferences may or may not be sensitive to the choice of prior.