*********SIBLINGS DATA ANALYSIS********
clear
set more off
capture log close
/*set mem 100000*/

use "C:\Users\John\Documents\Teach\ox_course\siblings.dta", clear
log using "C:\Users\John\Documents\Teach\ox_course\siblings.log", replace

la var x "number of siblings identified in data"
xtset mapid pid
xtdes
xtsum age sex years payears mayears yob misspa aveyears lnpay avelnpay x pahgs mahgs plbornc
xtsum age sex years payears mayears yob misspa aveyears lnpay avelnpay x pahgs mahgs plbornc if age>=22 & x>1 & x~=.

ta x if age>=22 
***CALCULATE SIBING CORRELATION IN YEARS OF EDUCATION FOR SIBLINGS AGED >21 AND AT LEAST 2 SIBS IN DATA**
xtreg years if age>=22 & x>1 & x~=., re
***CONTROL FOR AGE AND SEX IN CALCULATING THE CORRELATION**
xtreg years age sex if age>=22 & x>1 & x~=.,  re

**REGRESS YEARS OF EDUCATION ON AVERAGE PARENTS' YEARS OF EDUCATION**
xtreg years aveyears age sex if age>=22 & x>1 & x~=., re
xttest0
**REGRESS YEARS OF EDUCATION ON MOTHER'S YEARS OF EDUCATION**
xtreg years mayears age sex if age>=22 & x>1 & x~=., re

**REGRESS YEARS OF EDUCATION ON MOTHER'S AND FATHER'S YEARS OF EDUCATION**
xtreg years mayears payears age sex if age>=22 & x>1 & x~=., re

***ANALYSIS OF LOG PAY OF SIBLINGS***
***REGRESS LOG PAY ON OWN YEARS OF EDUCATION**
xtreg lnpay years age sex if age>=22 & x>1 & x~=., re
xttest0
***ALSO CONTROL FOR PARENTS' EDUCATION**
xtreg lnpay years age sex aveyears if age>=22 & x>1 & x~=., re
xtreg lnpay years age sex mayears payears  if age>=22 & x>1 & x~=., re


exit