* Working Econ. 435 assignment # 6
* Employment, persons aged 20-24 years - seasonally adjusted
set nocolor
time 1976 12
sample 1976.1 1999.1
genr x=time(0)
genr x2=x**2
genr x3=x**3
read(a:d980598.txt) d980598/skiplines=3
read(a:b14079.txt) b14079/skiplines=20
stat b14079
sample 1983.1 1998.12
read(a:l95668.txt) l95668/skiplines=19
stat l95668
* Skipping missing data on the interest rate
sample 1983.1 1995.4 1996.1 1998.11
* Doing regressions without TIME
ols d980598 b14079 l95668/rstat resid=r predict=yh
diagnos/het
arima r/plotac plotpac
sample 1983.1 1995.4 1996.2 1998.11
auto d980598 b14079 l95668/rstat
* "Correcting" for heteroscedasticity
sample 1983.1 1995.4 1996.1 1998.11
genr wt=1/(yh**2)
ols d980598 b14079 l95668/rstat weight=wt
* Doing regressions with TIME
ols d980598 b14079 l95668 x x2 x3/rstat resid=rr
diagnos/het
arima rr/plotac plotpac
* Note skipped MD for lag term (AUTO) at break as well
sample 1983.1 1995.4 1996.2 1998.11
auto d980598 b14079 l95668 x x2 x3/rstat