dset <- read.csv("psample.csv", header=TRUE)
dset <- plm.data(dset,index = c("pref","year"))
panel.fe <- plm(y ~ x1 + x2,data = dset, model = "within")
summary(panel.fe)
summary(fixef(panel.fe))
panel.re <- plm(y ~ x1 + x2,data = dset, model = "random")
summary(panel.re)
phtest(panel.fe,panel.re)