model{
    for(i in 1:n){
      y[i] ~ dnorm(mu[i],tau)
      mu[i] <- b0 +b[1]*X[i,1]+b[2]*X[i,2]+b[3]*X[i,3]
    }
    b0 ~ dnorm(0,0.001)
    tau ~ dgamma(0.001,0.001)
    for(j in 1:3){
       b[j] ~ dnorm(0,0.001)  
    }
}