library(AER)

#restringir salarios observados
oursample <- subset(MROZ, !is.na(wage))

#estimar 2SLS
ivreg1<-ivreg(log(wage)~educ+exper+I(exper^2)|motheduc+fatheduc+exper+I(exper^2), data=oursample)

#teste Hausmann
summary(ivreg1, diagnostics=TRUE)