I have a logistic regression model in GeoBugs to estimate predictors of prevalence of a disease. Can anyone tell me if there is a simple way to determine the lower and upper bounds of phi for spatial.exp.
This is part of the model:
Infected[i] ~ dbin(p[i], tested[i]) logit(p[i]) <- alpha + beta1*covar1[i] + beta2*covar2[i] + u[i] mu[i] <- 0 u[1:N] ~ spatial.exp(mu, x, y, tau, phi, 1)
This how I have specified the priors:
phi ~ dunif(0.25, 20)
At the moment my selection has been arbitrary. The GeoBugs manual only goes as far as saying that the bounds of the distribution are determined by the data.
What I would like to know is there a dummies version of the best way to select the values.