pdf("rpd3_1r.pdf") X <- matrix(c(1,0.02,1,0.07,1,0.11,1,0.15),byrow=T,ncol=2) Y <- matrix(c(242,237,231,201),ncol=1) XPX <- t(X) %*% X XPY <- t(X) %*% Y XPXINV <- solve(XPX) BETAHAT <- XPXINV %*% XPY P <- X %*% XPXINV %*% t(X) YHAT <- P %*% Y I4 <- diag(1,nrow=4,ncol=4) e <- (I4-P) %*% Y X Y XPX XPY XPXINV BETAHAT P YHAT e dev.off()