?****************************************
? Problem Set 6
? Tutorial in Microeconometrics
? Summer term 2008
? Katrin Sommerfeld
?****************************************

options crt;
freq N;

read (file='L:Microeconometrics\minwage.raw') psoda1 pfries1 pburger1 wage1 emp1
psoda2 pfries2 pburger2 wage2 emp2 compown BK KFC Rogers Wendys state;

msd(terse) @all;

title 'New Jersey';
select state=1;
?hist(percent) wage1 wage2;
msd(terse) wage1 wage2 emp1 emp2;
select 1;

title 'Pennsylvania';
select state=0;
?hist(percent) wage1 wage2 ;
msd(terse) wage1 wage2 emp1 emp2;
select 1;

? Exercise 3
title 'Restaurants with minimum wage before reform';
select state=1;
select wage1=4.25;
msd(terse) emp1 emp2 wage1 wage2 psoda1 pfries1 pburger1 psoda2 pfries2 pburger2;
select 1;

title 'Restaurants with wage between old and new minimum wage before reform';
select state=1;
select wage1>4.25 & wage1<5.05;
msd(terse) emp1 emp2 wage1 wage2 psoda1 pfries1 pburger1 psoda2 pfries2 pburger2;
select 1;

title 'Restaurants paying at least new minimum wage already before reform';
select state=1;
select wage1>=5.05;
msd(terse) emp1 emp2 wage1 wage2 psoda1 pfries1 pburger1 psoda2 pfries2 pburger2;
select 1;

? Exercise 4
title 'New Jersey';
select state=1;
msd(terse) psoda1 pfries1 pburger1 psoda2 pfries2 pburger2;
select 1;

title 'Pennsylvania';
select state=0;
msd(terse) psoda1 pfries1 pburger1 psoda2 pfries2 pburger2;
select 1;

? Exercise 5: Diff-in-Diff

select state=1;
msd emp1;
set E1NJ=@mean;
msd emp2;
set E2NJ=@mean;
select 1;

select state=0;
msd emp1;
set E1PEN=@mean;
msd emp2;
set E2PEN=@mean;
select 1;

set DID=(E2NJ-E1NJ)-(E2PEN-E1PEN);
print DID;

? 6. Additional Exercise: Regression of change
genr DE=emp2-emp1;
olsq DE c compown BK KFC Wendys state;

end;