gistfile1.r

(b1 <- sum((x-mean(x))*(y-mean(y)))/sum((x-mean(x))^2)) 
(b0 <- mean(y)-b1*mean(x))
yhat <- b0+b1*x
e <- y-yhat
SSE <- sum(e^2)
MSE <- SSE/(length(y)-2)

plot(faithful$waiting,faithful$eruptions,main="Old Faithful",xlab="Wait time (minutes)",
		ylab="Eruption duration (minutes)")

plot(iris$Sepal.Width,iris$Sepal.Length,main="Can we predict lenght from width?",
		xlab="Sepal width",ylab="Sepal lentgh")

plot(iris$Sepal.Width,iris$Sepal.Length,main="Can we predict lenght from width?",
		xlab="Sepal width",ylab="Sepal lentgh",pch=as.numeric(iris$Species))