huyanqing=function(n,l,d,m){
k=1;i=1;o=1;y=matrix(NA,10,500);B=NULL
x=c(runif(n))            
for(k in 1:l){               
s=c(rnorm(n))   
y[,k]=x+s  
k=k+1  
}
for(o in 1:d){
for(i in 1:m){
X2=sample(1:500,1,replace=TRUE)
A=matrix(NA,10,2)
A[,i]=y[,X2]
i=i+1
}
lm.reg<-lm(A[,1]~A[,2])
U=summary(lm.reg)$coefficients[2, 3]
B=c(B,U)
o=o+1
}
quantile(B,c(0.1,0.5,99.5)/100)
}