clear
use "C:\Users\kaewkwan\Desktop\EE325\Table8.8.dta" 

/*EE325*/
/*STATA session II*/

/*question1*/
/*Example Restricted Least Squares: Testing Linear Equality Restrictions*/

gen lnGDP = log(GDP)
gen lncapital = log(capital)
gen lnemployment = log(employment)
reg lnGDP lncapital lnemployment

global xlist lncapital lnemployment
reg lnGDP $xlist

gen GDPemployment = GDP/employment
gen lnGDPemployment = log(GDPemployment)
gen clratio=capital/employment
gen lnclratio = log(clratio)
bro
reg lnGDPemployment lnclratio

clear
use "C:\Users\kaewkwan\Desktop\EE325\Table9.1.dta" 

/*Question 2*/

reg salary d2 d3


clear
use "C:\Users\kaewkwan\Desktop\EE325\Table9.4.dta" 

/*Seasonal analysis-class example*/

gen d1=0
replace d1=1 if d2==0&d3==0&d4==0
bro

/*Without intercept term*/
reg frig d1 d2 d3 d4
reg frig d1 d2 d3 d4, nocon

reg frig d2 d3 d4


clear
use "C:\Users\kaewkwan\Desktop\EE325\Table8.9.dta" 

/*question 3*/
/*Chow test*/
reg savings income if year<1982
reg savings income if year>1981
reg savings income

/*The Dummy Variable Alternative to the Chow test*/
gen d =0
replace d=1 if year>1981
gen dx =income*d

reg savings d income dx

clear

use "C:\Users\kaewkwan\Desktop\EE325\Table9.7.dta" 

/*question 4*/
gen lnwi=log(wi)
/*equation 1*/
reg lnwi age de2 de3 de4 dpt

/*interaction term*/
gen dsexde2=dsex*de2
gen dsexde3=dsex*de3
gen dsexde4=dsex*de4

/*equation 2*/
reg lnwi age de2 de3 de4 dsexde2 dsexde3 dsexde4 dpt

/*equation 3*/
reg lnwi age dsex dsexde2 dsexde3 dsexde4 dpt

clear
/*Multicollinearity*/
/*lecture class example*/
/*Example 1*/
/*Table10.5*/
use "C:\Users\kaewkwan\Desktop\EE325\Table 10.5.dta" 
reg y x2 x3
/*High R squared but insignificant t statistics*/ 
/*Reject overall test -F test*/
corr x2 x3
vif

reg y x2
reg y x3

clear
/*Multicollinearity*/
/*lecture class example*/
/*Example 2*/
/*Table10.7*/
use "C:\Users\kaewkwan\Desktop\EE325\Table 10.7.dta" 
gen lnc=log(c)
gen lnyd=log(yd)
gen lnw=log(w)
reg lnc lnyd lnw i
corr c yd w i
vif