# exemplos com variaveis binarias e teste de Chow

wage1 <- read.table("C:/Users/Gui/FEA/guilherme/FEARP/graduação/econometria/Wooldridge - dados em excel com cabecalho/WAGE1.raw", header=TRUE, sep="", na.strings="NA", dec=".", strip.white=TRUE)
attach(wage1)

wage1[1,]

#gerando variáveis binárias

#gera dummy para brancos

white<- as.numeric(nonwhite==0)

white[20:30]
nonwhite[20:30]

#gera dummy para educa<10 e outra para educa>=10

educa0.10 <- as.numeric(educ>=0 &educ<10)
educa10.more <- as.numeric(educ>9)

educ[1:10]
educa0.10 [1:10]
educa10.more [1:10]

#teste de Chow

regu<-lm(lwage~educ+exper+married+west+educ*west+exper*west+married*west)
regp <- lm(lwage~educ+exper+married) 
reg1 <- lm(lwage~educ+exper+married, subset=(west==1)) 
reg2 <- lm(lwage~educ+exper+married, subset=(west==0)) 

uhatu<-(regu$resid)^2
uhatp<-(regp$resid)^2
uhat1<-(reg1$resid)^2
uhat2<-(reg2$resid)^2

rssu<-sum(uhatu)
rssp<-sum(uhatp)
rss1<-sum(uhat1)
rss2<-sum(uhat2)

rss1+rss2

rssu

detach(wage1)