cat("\n")
cat("See F.J. Anscombe, American Statistician 27 (1973 February), \n")
cat("17-21.  See also start of E.R. Tufte, The Visual Display \n")
cat("of Quantitative Information, Cheshire, CT: Graphics Press \n")
cat("1983. \n")
cat("\n")
data(anscombe)
print(anscombe)
attach(anscombe)
cat("\n")
cat("   ",mean(x1),var(x1),mean(y1),var(y1),cov(x1,y1),"\n")
cat("   ",mean(x2),var(x2),mean(y2),var(y2),cov(x2,y2),"\n")
cat("   ",mean(x3),var(x3),mean(y3),var(y3),cov(x3,y3),"\n")
cat("   ",mean(x4),var(x4),mean(y4),var(y4),cov(x4,y4),"\n")
f1 <- lm(y1 ~ x1)
f2 <- lm(y2 ~ x2)
f3 <- lm(y3 ~ x3)
f4 <- lm(y4 ~ x4)
print(f1)
print(f2)
print(f3)
print(f4)
plot(y1,x1,pch="1")
plot(x2,y2,pch="2")
plot(x3,y3,pch="3")
plot(x4,y4,pch="4")
plot(y1,x1,pch="1")
points(x2,y2,pch="2")
points(x3,y3,pch="3")
points(x4,y4,pch="4")