SLID1 <- read.table("c:/temp/SLID-Ontario.txt",sep = "\t",header=F,skip=1)
names(SLID1)  <- c("age","sex","wages","yearsed")

SLID1$male <- as.numeric(SLID1$sex == "Male")


library(MASS)

 # plotting the log-likelihood function for the Box-Cox transformation
 # start with a broader range
SLID1BC <- boxcox(wages ~ male +age +yearsed, data=SLID1,
        lambda = seq(-2.00, 2.00, length = 50))

 # zoom in for a closer look
SLID1BC <- boxcox(wages ~ male +age +yearsed, data=SLID1,
        lambda = seq(-.25, .25, length = 50))




 # the function box.cox.var in the car package creates the constructed variable

library(car)

SLID1.lm1BC <- lm(wages ~ male +age +yearsed +box.cox.var(wages), data=SLID1)

av.plots(SLID1.lm1BC,"box.cox.var(wages)")