#Open R commander
ADD=read.table("http://www.unt.edu:8080/rss/class/mike/data/Add.dat", header=T)


library(Rcmdr)
#12. First multiple regression.
mymodel <- lm(GPA~Gender+IQ, data=ADD)
summary(mymodel)
#13. Open relaimpo
library(relaimpo)
#14. Calculate relative importance
calc.relimp(mymodel, rela=T)
#15. Add ADDSC to model
mymodel2 <- lm(GPA~ADDSC+Gender+IQ, data=ADD)
summary(mymodel2)
#16. Calculate new relative importance
calc.relimp(mymodel2, rela=T)