#  2005 年 06 月 29 日作成
# drawing confidence intervals from normal sample
# nunmber of repitaion
no.rep<-49
# sample size
no.sam<-10
# quantile
z<-qnorm(0.95,0,1)
for (i in 1:no.rep){
x<-rnorm(no.sam,2,1)
confi<-c(mean(x)-z/sqrt(no.sam),mean(x)+z/sqrt(no.sam))
par(new=T)
plot(i,mean(x),xlab="",ylab="",main="",xlim=c(-1,no.rep),segments(i,confi[1],i,confi[2]),ylim=c(0,4))
}
abline(2,0)
x<-rnorm(no.sam,2,1)
confi<-c(mean(x)-z/sqrt(no.sam),mean(x)+z/sqrt(no.sam))
par(new=T)
plot(i,mean(x),xlab="",ylab="",main="confidence interval, sample size=10,sig=0.9,rep=50",xlim=c(-1,no.rep),segments(i,confi[1],i,confi[2]),ylim=c(0,4))