Commit 6af97bef by Robert Ricci

### R commands to use with the lecture

parent 7957a793
 x = c(1.2, 2.4, 2.9, 4.0, 4.8, 6.1, 7.2, 7.9, 9.3) y = c(1.1, 2.2, 3.1, 4.4, 5.0, 5.1, 7.2, 8.3, 9.1) plot(x,y, cex=5) b1 = (sum(x*y) - length(x)*mean(x)*mean(y))/(sum(x^2) - length(x)*(mean(x)^2)) b0 = mean(y) - b1*mean(x) abline(b0,b1, lwd=5) f <- function(x) b0 + b1*x plot(x,sapply(x,f), cex=5) r = y - sapply(x,f) plot(x,r, cex=5) ----- x = seq(1,100,by=1) y = sapply(x, function(x) (x^1.4 + rnorm(1,0,10))) plot(x,y, cex=5) b1 = (sum(x*y) - length(x)*mean(x)*mean(y))/(sum(x^2) - length(x)*(mean(x)^2)) b0 = mean(y) - b1*mean(x) abline(b0,b1, lwd=5) f <- function(x) b0 + b1*x plot(x,sapply(x,f), cex=5) r = y - sapply(x,f) plot(x,r, cex=5) ----- lm(y ~ x) ----- model = lm(y ~ poly(x,2,raw=TRUE)) plot(x,y, cex=5) lines(x, predict(model, data.frame(x=x)), lwd=5) r = y - predict(model, data.frame(x=x)) plot(x,r) r = y - sapply(x, function(x) (-11.26668 + x*3.51530 + x^2*0.02947))
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