# NOT RUN {
## Stock and Watson (2007)
## data and transformations
data("CigarettesSW")
CigarettesSW$rprice <- with(CigarettesSW, price/cpi)
CigarettesSW$rincome <- with(CigarettesSW, income/population/cpi)
CigarettesSW$tdiff <- with(CigarettesSW, (taxs - tax)/cpi)
c1985 <- subset(CigarettesSW, year == "1985")
c1995 <- subset(CigarettesSW, year == "1995")
## convenience function: HC1 covariances
hc1 <- function(x) vcovHC(x, type = "HC1")
## Equations 12.9--12.11
fm_s1 <- lm(log(rprice) ~ tdiff, data = c1995)
coeftest(fm_s1, vcov = hc1)
fm_s2 <- lm(log(packs) ~ fitted(fm_s1), data = c1995)
fm_ivreg <- ivreg(log(packs) ~ log(rprice) | tdiff, data = c1995)
coeftest(fm_ivreg, vcov = hc1)
## Equation 12.15
fm_ivreg2 <- ivreg(log(packs) ~ log(rprice) + log(rincome) | log(rincome) + tdiff, data = c1995)
coeftest(fm_ivreg2, vcov = hc1)
## Equation 12.16
fm_ivreg3 <- ivreg(log(packs) ~ log(rprice) + log(rincome) | log(rincome) + tdiff + I(tax/cpi),
data = c1995)
coeftest(fm_ivreg3, vcov = hc1)
## More examples can be found in:
## help("StockWatson2007")
# }
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