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Unit Root Test

Posted: Fri Apr 13, 2012 7:44 pm
by tgmoe
For the unit root test, what is the hypothesis being tested? Is it,
yt = pyt-1 + et
H0: p=1 v. Ha: p<1
or
Δyt = ayt-1 + et where a = p-1
H0: a=0 v. Ha: a<0

Thanks for any help!

Re: Unit Root Test

Posted: Fri Apr 13, 2012 8:30 pm
by startz
Aren't those identical?

Re: Unit Root Test

Posted: Sat Apr 14, 2012 2:19 pm
by tgmoe
Yes, I was unclear. What I mean to ask is in the Dickey-Fuller Unit Root Test which hypothesis is being tested? a=0 or p=1.

Unit Root Test

Posted: Sat Apr 14, 2012 4:52 pm
by EViews Gareth
If a=p-1 then they're the same.