consump.dat
*
* Baltagi, Econometrics, 3rd edition
* Unit Root tests from pp 370-371
*
open data consump.dat
calendar 1950
data(format=prn,org=columns) 1950:1 1993:1 year y c
*
* Dickey-Fuller regression, done directly
*
set dc = c-c{1}
set trend = t-1
linreg dc
# constant trend c{1}
*
* Using DFUNIT instead.
*
@dfunit(det=trend) c
@dfunit(det=trend,lags=2) c
*
* Unit root tests on the difference
*
@dfunit dc
Linear Regression - Estimation by Least Squares
Dependent Variable DC
Annual Data From 1951:01 To 1993:01
Usable Observations 43
Degrees of Freedom 40
Centered R^2 0.1784226
R-Bar^2 0.1373437
Uncentered R^2 0.6364631
Mean of Dependent Variable 176.06976744
Std Error of Dependent Variable 158.71453790
Standard Error of Estimate 147.41293829
Sum of Squared Residuals 869222.97497
Regression F(2,40) 4.3434
Significance Level of F 0.0196322
Log Likelihood -274.1687
Durbin-Watson Statistic 1.2950
Variable Coeff Std Error T-Stat Signif
************************************************************************************
1. Constant 1088.862035 367.687722 2.96138 0.00513184
2. TREND 39.901642 14.313438 2.78770 0.00808331
3. C{1} -0.195606 0.073976 -2.64419 0.01164097
Dickey-Fuller Unit Root Test, Series C
Regression Run From 1951:01 to 1993:01
Observations 44
With intercept and trend
Using 0 lags on the differences
Sig Level Crit Value
1%(**) -4.17815
5%(*) -3.51361
10% -3.18677
T-Statistic -2.64419
Dickey-Fuller Unit Root Test, Series C
Regression Run From 1953:01 to 1993:01
Observations 42
With intercept and trend
Using 2 lags on the differences
Sig Level Crit Value
1%(**) -4.18957
5%(*) -3.51887
10% -3.18977
T-Statistic -2.85679
Dickey-Fuller Unit Root Test, Series DC
Regression Run From 1952:01 to 1993:01
Observations 43
With intercept
Using 0 lags on the differences
Sig Level Crit Value
1%(**) -3.58883
5%(*) -2.93030
10% -2.60296
T-Statistic -4.43044**