Cwomen1 <- read.table("c:/temp/BFox.txt",header=F,skip=1)
names(Cwomen1)  <- c("year","participation","tfr","menWages","womenWages","debt","parttime") 

Cwomen1$tfr  <- Cwomen1$tfr*(Cwomen1$year != 1973) +1931*(Cwomen1$year == 1973)

Cwomen1.lm1 <- lm(participation ~ tfr +menWages +womenWages +debt +parttime +year, data=Cwomen1)

 # A ridge regression function is available in the MASS library

library(MASS)

Cwomen.lmridge <- lm.ridge(participation ~ tfr +menWages 
                +womenWages +debt +parttime +year, data=Cwomen1,lambda = seq(0,0.2,0.005))

plot(Cwomen.lmridge,lambda = seq(0,0.2,0.005))


Cwomen.lmridge$kHKB

Cwomen.lmridge$kLW

Cwomen.lmridge$GCV

plot(Cwomen.lmridge$GCV)