#nls80-script1.R import nls80 from stata files
#and do some fooling around

library(foreign) #for import of data via read.dta()
library(Hmisc)   #for latex output via latexVerbatim()

read.dta("NLS80.DTA")->nls80
colnames(nls80) <- c('wage','hours','iq','kww','educ','exper','tenure','age',      
'married','black','south','urban','sibs','brthord','meduc','feduc','lwage')
attach(nls80)

#set up some convenient dummies
ed9 <- educ==9
ed10 <- educ>=10
ed11 <- educ>=11
ed12 <- educ>=12
ed13 <- educ>=13
ed14 <- educ>=14
ed15 <- educ>=15
ed16 <- educ>=16
ed17 <- educ>=17
ed18 <- educ>=18
expersq <- exper^2

reg1 <- lm(lwage~educ+exper)
reg2 <- lm(lwage~ed10+ed11+ed12+ed13+ed14+ed15+ed16+ed17+ed18+exper)

dfnum <- (length(reg2$coef)-length(reg1$coef))
Fnum <- (sum(reg1$residuals^2)-sum(reg2$residuals^2))/dfnum
dfden <- length(reg2$residuals)-length(reg2$coef)
Fden <- sum(reg2$residuals^2)/dfden
Ftest <- Fnum/Fden
print(pf(Ftest,dfnum,dfden))

ed9 <- educ==9
ed10 <- educ==10
ed11 <- educ==11
ed12 <- educ==12
ed13 <- educ==13
ed14 <- educ==14
ed15 <- educ==15
ed16 <- educ==16
ed17 <- educ==17
ed18 <- educ==18

reg3 <- lm(lwage~ed10+ed11+ed12+ed13+ed14+ed15+ed16+ed17+ed18+exper)
summary(reg3)->summary.reg3
latexVerbatim(summary.reg3)
summary(reg2)->summary.reg2
latexVerbatim(summary.reg2)
print(summary(reg3))