108
METODOLOGÍA PARA ESTIMAR EL USO EFICIENTE DEL AGUA EN ACTIVIDADES AGRICOLAS
Breusch-Pagan / Cook-Weisberg test for heteroskedasticity
Ho: Constant variance
Variables: fitted values of PBrB
chi2(1) = 5.90
Prob > chi2 =
0.0151
White’s test for Ho: homoskedasticity
against Ha: unrestricted heteroskedasticity
chi2(2) = 7.05
Prob > chi2 =
0.0295
Cameron &Trivedi’s decomposition of IM-test
Source
|
Chi2
df
p
----------------------------- + -----------------------------------------------------------
Heteroskedasticity
|
7.05
2
0.0295
Skewness
|
2.34
1
0.1260
Kurtosis
+ 1.09
1
0.2970
-------------------------------------------------------------------------------------------------
Total
|
10.48
4
0.0331
-------------------------------------------------------------------------------------------------
En la estimación de la producción de Broccoli, se corrigió por heteroscedascidad con la estimación
robusta de las desviaciones estándar de los coeficientes, para hacerlos consistentes.
Linear regression
Number of obs
= 41
F( 1, 39)
=
329.59
Prob > F
= 0.0000
R-squared
=
0.9203
Root MSE
=
1240.5
----------------------------------------------------------------------------------------------------------------------------------------------
|
Robust
[95% Conf. Interval]
PBrB
|
Coef
Std. Err.
t
P>|t|
------------------- + -------------------------------------------------------------------------------------------------------------------
ABrB
|
1.237155 .0681452
18.15
0.000
1.099319 1.374992
_cons
|
1117.521
194.3415
5.75
0.005
724.4281
1510.614
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