Creates the vague (reference) prior for the parameters of a normally distributed endpoint. For one endpoint the prior density is \(p(\mu, \sigma^2) \propto \sigma^{-2}\); for two endpoints it is \(p(\mu, \Sigma) \propto |\Sigma|^{-3/2}\). With \(n\) observations the posterior distribution of the mean is a t distribution with \(n - 1\) degrees of freedom for one endpoint and a bivariate t distribution with \(n - 2\) degrees of freedom for two endpoints.
See also
Other priors:
prior_beta(),
prior_dirichlet(),
prior_gamma(),
prior_niw(),
prior_nix()