1. Pes dels nadons i paquets de cigarretes fumats per la mare

2. cor(packs, lbwght) r = -0.1406743 library(foreign)
data=read.dta("E:/DATA/WooldridgeBook/bwght.dta")
names(data)
attach(data)
dim(data)
plot(packs, lbwght)
abline(lm(lbwght~packs))
lm(lbwght~packs)
cor(packs, lbwght)
r =

3. plot(lm(lbwght ~packs))
Y = X
(0.017)
-5.29

4. plot(lm(lbwght ~packs))

10. lm(lbwght~packs)
Coefficients:
(Intercept) packs
lm(packs~fatheduc)
(Intercept) fatheduc
lm(packs~motheduc)
(Intercept) motheduc
lm(lbwght~motheduc)
lm(lbwght~fatheduc)