请教各位：关于《高等数理统计》茆诗松、王静龙和濮晓龙编著的那本教材中关于WINBUGS第六章中有一个程序，455页，我按照书上说的在WINBUGS上运行，可是在模型编辑时运行结果显示：变量N未被定义，到底是那个地方出错了呢？请教各位啊
书上的程序列在下面：
model
{
for(i in 1:N)
{
r~dbin(p,n)
b~dnorm(0,tau)
logit(p)<-alpha0+alpha1*x1+alpha2*x2+alpha12*x1*x2+b
}
alpha0~dnorm(0.0,1.0E-6)
alpha1~dnorm(0.0,1.0E-6)
alpha2~dnorm(0.0,1.0E-6)
alpha12~dnorm(0.0,1.0E-6)
tau~dgamma(0.001,0.001)
sigma<-1/sqrt(tau)
}
list(
r=c(10,23,23,26,17,5,53,55,32,46,10,8,10,8,23,0,
3,22,15,32,3)
n=c(39,62,81,51,39,6,74,72,51,79,13,16,30,28,45,
4,12,41,30,51,7)
x1=c(0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1)
x2=c(0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1,1)
N=21
)
list(
alpha0=0,alpha1=0,alpha2=0,alpha12=0,tau=1
)
书上的程序列在下面：
model
{
for(i in 1:N)
{
r~dbin(p,n)
b~dnorm(0,tau)
logit(p)<-alpha0+alpha1*x1+alpha2*x2+alpha12*x1*x2+b
}
alpha0~dnorm(0.0,1.0E-6)
alpha1~dnorm(0.0,1.0E-6)
alpha2~dnorm(0.0,1.0E-6)
alpha12~dnorm(0.0,1.0E-6)
tau~dgamma(0.001,0.001)
sigma<-1/sqrt(tau)
}
list(
r=c(10,23,23,26,17,5,53,55,32,46,10,8,10,8,23,0,
3,22,15,32,3)
n=c(39,62,81,51,39,6,74,72,51,79,13,16,30,28,45,
4,12,41,30,51,7)
x1=c(0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1)
x2=c(0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1,1)
N=21
)
list(
alpha0=0,alpha1=0,alpha2=0,alpha12=0,tau=1
)