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library(AER);library(stargazer)
data(mroz, package=’wooldridge’)

str(mroz)
head(mroz)
summary(mroz)

# restrict to non-missing wage observations
oursample <- subset(mroz, !is.na(wage))         #驚嘆號是not的意思
oursample

 

#
ols<-lm(log(wage)~educ+exper+I(exper^2) , data=oursample)

oursample$exp2 <- oursample$exper^2
lm(log(wage)~educ+exper+exp2 , data=oursample)
ols

 

# 1st stage: reduced form
stage1 <- lm(educ~exper+I(exper^2)+motheduc+fatheduc, data=oursample)

# 2nd stage
man.2SLS<-lm(log(wage)~fitted(stage1)+exper+I(exper^2), data=oursample)

# Automatic 2SLS estimation
aut.2SLS<-ivreg(log(wage)~educ+exper+I(exper^2)
| motheduc+fatheduc+exper+I(exper^2) , data=oursample)

# Pretty regression table
stargazer(ols,stage1,man.2SLS,aut.2SLS,type=”text”,keep.stat=c(“n”,”rsq”))

221124 計量經濟學_1
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