use "C:\Users\Asus\Documents\AUCA\Teaching\2022-2023\Econometrics I\Seminars\Seminar 9\Card.dta" 
regress educ nearc4 exper expersq black smsa south reg662 reg663 reg664 reg665 reg666 reg667 reg668 reg669
predict v2, residuals
regress lwage educ exper expersq black smsa south reg662 reg663 reg664 reg665 reg666 reg667 reg668 reg669 v2
ivregress 2sls lwage exper expersq black smsa south reg662 reg663 reg664 reg665 reg666 reg667 reg668 reg669 (educ = nearc4 nearc2)
predict u1hat, residuals
regress u1hat nearc4 nearc2 exper expersq black smsa south reg662 reg663 reg664 reg665 reg666 reg667 reg668 reg669
use "C:\Users\Asus\Documents\AUCA\Teaching\2022-2023\Econometrics I\Seminars\Seminar 9\wage2.dta", clear
ivregress 2sls lwage exper tenure black (educ = sibs)
regress educ sibs exper tenure black
predict educ_hat
regress lwage educ_hat exper tenure black
regress educ sibs
predict educ_tilde
regress lwage educ_tilde exper tenure black
use "C:\Users\Asus\Documents\AUCA\Teaching\2022-2023\Econometrics I\Seminars\Seminar 9\htv.dta", clear
regress lwage educ
regress educ ctuit
regress lwage educ expersq ne west south ne18 south18 west18 urban urban18
regress educ ctuit expersq ne west south ne18 south18 west18 urban urban18
ivregress 2sls lwage expersq ne west south ne18 south18 west18 urban urban18 (educ = ctuit)