Example 6.3 Predictive distribution of Power

model
{
tau.s <- 1/pow(.3,2)      # transform sd to precision=1/sd2
tau.d <- 1/pow(.1,2)
s ~ dnorm(1, tau.s)I(0,)
d ~ dnorm(.5, tau.d)I(0,)
n<- 2 * pow(    (.84 +1.96) * s / d ,  2 )
power <- phi(  sqrt(63/2)* d /s  -1.96  )
prob70 <-step(power-.7)
}