* Question 3

use "Problem_Set_09_Data.dta", clear

* (b)
regress p a wg g t p1 x1 k1
testparm g t wg a x1

* (c)
predict phat, xb
regress i phat p1 k1

* (d)
ivreg i p1 k1 (p = a x1 p1 t g wg k1)

* (e)
regress i p p1 k1