var x[N], Y[N], mu[N], alpha, beta, tau, sigma, x.bar;
model {
  for (i in 1:N) {
    mu[i] <- alpha + beta*(x[i] - x.bar);
    Y[i]   ~ dnorm(mu[i],tau);
  }
  x.bar   <- mean(x[]);
  alpha    ~ dnorm(0.0,1.0E-4);
  beta     ~ dnorm(0.0,1.0E-4);
  tau      ~ dgamma(1.0E-3,1.0E-3);
  sigma   <- 1.0/sqrt(tau);
}