## Wart removal: 1 = duct tape, 2= liquid nitrogen # Uniform prior: model { for (i in 1:2) { y[i] ~ dbin(p[i], n[i]) p[i] ~ dunif(0,1) } post <- step(p[1]-p[2]) } list(n=c(100,104), y=c(60,88)) # Jeffreys' prior: model { for (i in 1:2) { y[i] ~ dbin(p[i], n[i]) p[i] ~ dbeta(0.5,0.5) } post <- step(p[1]-p[2]) } list(n=c(100,104), y=c(60,88)) ##################################################### ## College registration: 1 = telephone, 2= online # Uniform prior: model { for (i in 1:2) { y[i] ~ dbin(p[i], n[i]) p[i] ~ dunif(0,1) } post <- step(p[1]-p[2]) } list(n=c(80,60), y=c(57,50)) # Jeffreys' prior: model { for (i in 1:2) { y[i] ~ dbin(p[i], n[i]) p[i] ~ dbeta(0.5,0.5) } post <- step(p[1]-p[2]) } list(n=c(80,60), y=c(57,50)) ######################################################## #### Supernatural guessing example: # Lindley's prior: # change U(0.5,1) prior to be more skeptical model { p[1] <- theta[pick] pick ~ dcat(q[]) q[1] <- 0.5 q[2] <- 0.5 theta[1] <- 0.5 theta[2] ~ dunif(0.5, 1) r <- 8; n <- 8 r ~ dbin(theta[pick], n) psychic <- pick - 1 }