El 23/06/15 a las 14:39, Sven Schreiber escribió:
Hi,
now for something completely different: As I mentioned in passing at
the conference, I have received some (mild) complaints about the
output of the ADF test in gretl. And indeed I think the arrangement of
the information is suboptimal. So here's a concrete suggestion with
before-and-after [need to view this with monospaced font]:
Now / before:
"
Augmented Dickey-Fuller test for LRM
including 4 lags of (1-L)LRM
sample size 50
unit-root null hypothesis: a = 1
test with constant
model: (1-L)y = b0 + (a-1)*y(-1) + ... + e
1st-order autocorrelation coeff. for e: 0.075
lagged differences: F(4, 44) = 4.290 [0.0051]
estimated value of (a - 1): -0.0591989
test statistic: tau_c(1) = -1.70189
asymptotic p-value 0.4303
"
And my suggestion / after:
"
LRM: Augmented Dickey-Fuller test
(H0: unit root, a = 1)
-------------------------------------
Test with constant
â - 1 = -0.0591989
Test stat tau_c(1) = -1.70189
Asympt. p-value = 0.4303
-------------------------------------
Test equation:
Dependent variable differenced: (1-L)LRM,
lagged level with coefficient a - 1,
including 4 lagged differences
(exclusion test F(4, 44) = 4.290 [0.0051]),
and constant term.
Residual 1st-order autocorr = 0.075
Sample size = 50
--------------------------------------
"
Now I'm not saying my suggestion is optimal, but I do think it would
be an improvement. If somebody directs me to the right places in the
source, I could try to make the corresponding changes.
What do you think?
I like to divide the results into two parts, because it makes more
visible the important things of the test. I would do two changes (but
they are only a matter of different tastes):
1) Put the line 'â - 1 = -0.0591989' after the Asymp.p-value, so
that the calculated tau statistic may be seen as the first number.
2) I liked to see the model: (1-L)y = b0 + (a-1)*y(-1) + ... + e I
think it is a quick way of seeing what is the structure of the estimated
model.
--
Ignacio Díaz-Emparanza
Departamento de Economía Aplicada III (Econometría y Estadística)
Universidad del País Vasco - Euskalherriko Unibertsitatea, UPV/EHU
Tfno: (+34) 94 601 3732
http://www.ehu.eus/ea3