## Slide 4
pearson <- read.delim("../../data/pearson.txt")
pearson[1:10,]

## Slide 5
attach(pearson)
plot(Father,Son,pch=19,cex=.7)

## Slide 12-13
lm(y~x)

x <- pearson[,1]
y <- pearson[,2]

xx <- x - mean(x)
yy <- y - mean(y)

beta <- sum(xx*yy)/sum(xx^2)
alpha <- mean(y) - beta*mean(x)

## Slide 14
plot(Father,Son,pch=19,cex=.7,col="gray70")
abline(alpha,beta,lwd=2,col="blue")

## Slide 17
beta2 <- sum(xx*yy)/sum(yy^2)
alpha2 <- mean(y) - 1/beta2*mean(x)
plot(Father,Son,pch=19,cex=.7,col="gray70")
abline(alpha,beta,lwd=2,col="blue")
abline(alpha2,1/beta2,lwd=2,col="red")

## Slide 21
beta3 <- 1*sd(y)/sd(x)
alpha3 <- mean(y) - beta3*mean(x)
plot(Father,Son,pch=19,cex=.7,col="gray70")
abline(alpha,beta,lwd=2,col="blue")
abline(alpha3,beta3,lwd=2,lty=2)