x=rnorm(200)
hist(x,col="light blue")
rug(x)
stem(x)
x<-rnorm(500)
y<-x+rnorm(500)
plot(y~x)
a=lm(y~x)
summary(a)
abline(a,col="red")
print("Hello world")
paste("x的最小值=",min(x))
demo(graphics)