use "C:\Users\Asus\Documents\AUCA\Teaching\2022-2023\Econometrics I\Seminars\Seminar 2\Data\sleep75.dta" 
regress sleep totwrk
use "C:\Users\Asus\Documents\AUCA\Teaching\2022-2023\Econometrics I\Seminars\Seminar 2\Data\charity.dta"
sum gift
sum respond
sum mailsyear
reg gift mailsyear