R help - Feb 2012 - How are the coefficients for the ur.ers, type DF-GLS calculated?

I need some real help on this, really stuck

how are the coefficients for
ur.ers(y, type = c("DF-GLS", "P-test"), model =
c("constant", "trend"),
       lag.max = 0)

The max lag is set at zero, so the regression should simply be

Diff(zt) = a*z(t-1)

where a is the value i'm trying to find and z(t)'s are the detrended
values.
but through performing my own regression on the two time series I get
different values. This could only mean

1) Its not just a simple regression
or
2) I'm detrending my data incorrectly.

However, i've followed the instructions I've seen in research papers and
it
doesn't seem to be right. Basically I take Y*t = Yt-(1-(1-7/T)*Y(t-1) and
regress that on 1-(1-7/T)  for all t>1 and leave the values at T=1
unchanged. Then I take Yt and subtract the coefficient of the regression to
get the detrended value.

I'm really stuck on this and its really frustrating. I think the easiest
thing would be if someone can tell me exactly how R carries out the
calculations for the functions. Help will be highly appreciated!!


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Simply type ur.ers on a line by itself to see how the calculation is
implemented.

Michael

On Wed, Feb 29, 2012 at 11:20 AM, ackbar03 <wdai03 at gmail.com>
wrote:
> I need some real help on this, really stuck
>
> how are the coefficients for
> ur.ers(y, type = c("DF-GLS", "P-test"), model =
c("constant", "trend"),
> ? ? ? lag.max = 0)
>
> The max lag is set at zero, so the regression should simply be
>
> Diff(zt) = a*z(t-1)
>
> where a is the value i'm trying to find and z(t)'s are the
detrended values.
> but through performing my own regression on the two time series I get
> different values. This could only mean
>
> 1) Its not just a simple regression
> or
> 2) I'm detrending my data incorrectly.
>
> However, i've followed the instructions I've seen in research
papers and it
> doesn't seem to be right. Basically I take Y*t = Yt-(1-(1-7/T)*Y(t-1)
and
> regress that on 1-(1-7/T) ?for all t>1 and leave the values at T=1
> unchanged. Then I take Yt and subtract the coefficient of the regression to
> get the detrended value.
>
> I'm really stuck on this and its really frustrating. I think the
easiest
> thing would be if someone can tell me exactly how R carries out the
> calculations for the functions. Help will be highly appreciated!!
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/How-are-the-coefficients-for-the-ur-ers-type-DF-GLS-calculated-tp4432015p4432015.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Ackbar:

have a look at ur.ers directly. The coefficients can be recovered from the slot
'testreg', i.e.,

example(ur.ers)
slotNames(ers.gnp)
coef(ers.gnp at testreg)

RTFM: help("ur.ers") and help("ur.ers-class")

Best,
Bernhard


-----Urspr?ngliche Nachricht-----
Von: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Im
Auftrag von ackbar03
Gesendet: Mittwoch, 29. Februar 2012 17:20
An: r-help at r-project.org
Betreff: [R] How are the coefficients for the ur.ers, type DF-GLS calculated?

I need some real help on this, really stuck

how are the coefficients for
ur.ers(y, type = c("DF-GLS", "P-test"), model =
c("constant", "trend"),
       lag.max = 0)

The max lag is set at zero, so the regression should simply be

Diff(zt) = a*z(t-1)

where a is the value i'm trying to find and z(t)'s are the detrended
values.
but through performing my own regression on the two time series I get different
values. This could only mean

1) Its not just a simple regression
or
2) I'm detrending my data incorrectly.

However, i've followed the instructions I've seen in research papers and
it doesn't seem to be right. Basically I take Y*t = Yt-(1-(1-7/T)*Y(t-1) and
regress that on 1-(1-7/T)  for all t>1 and leave the values at T=1 unchanged.
Then I take Yt and subtract the coefficient of the regression to get the
detrended value.

I'm really stuck on this and its really frustrating. I think the easiest
thing would be if someone can tell me exactly how R carries out the calculations
for the functions. Help will be highly appreciated!!


--
View this message in context:
http://r.789695.n4.nabble.com/How-are-the-coefficients-for-the-ur-ers-type-DF-GLS-calculated-tp4432015p4432015.html
Sent from the R help mailing list archive at Nabble.com.

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