How is the LM test calculated for Gretl for just a standard model.
I just ran a model
Model 5: OLS, using observations 1-2017
Dependent variable: nettfa
coefficient std. error t-ratio p-value
---------------------------------------------------------
const -20.9850 2.47202 -8.489 3.98e-017 ***
inc 0.770583 0.0614520 12.54 8.73e-035 ***
age25 0.0251267 0.00259339 9.689 9.96e-022 ***
male 2.47793 2.04778 1.210 0.2264
e401k 6.88622 2.12327 3.243 0.0012 ***
Mean dependent var 13.59498 S.D. dependent var 47.59058
Sum squared resid 3982124 S.E. of regression 44.48805
R-squared 0.127868 Adjusted R-squared 0.126134
F(4, 2012) 73.74763 P-value(F) 2.18e-58
Log-likelihood -10514.46 Akaike criterion 21038.91
Schwarz criterion 21066.96 Hannan-Quinn 21049.21
When I save the residuals squared to run the Pagan test I get this
Model 6: OLS, using observations 1-2017
Dependent variable: usq5
Coefficient
Std. Error
t-ratio
p-value
const
-4573.55
1848.7
-2.4739
0.01345
**
inc
112.358
45.9568
2.4449
0.01458
**
age25
4.84866
1.93946
2.5000
0.01250
**
male
2331.25
1531.43
1.5223
0.12810
e401k
1164.83
1587.89
0.7336
0.46330
Mean dependent var
1974.280
S.D. dependent var
33367.52
Sum squared resid
2.23e+12
S.E. of regression
33270.33
R-squared
0.007789
Adjusted R-squared
0.005817
F(4, 2012)
3.948695
P-value(F)
0.003387
Log-likelihood
-23861.35
Akaike criterion
47732.70
Schwarz criterion
47760.75
Hannan-Quinn
47742.99
The LM test from my understanding is n*r^2, which here would be 15.71
Using gretl's built in test I get the following:
Breusch-Pagan test for heteroskedasticity
OLS, using observations 1-2017
Dependent variable: scaled uhat^2
coefficient std. error t-ratio p-value
--------------------------------------------------------
const -2.31657 0.936391 -2.474 0.0134 **
inc 0.0569109 0.0232777 2.445 0.0146 **
age25 0.00245591 0.000982363 2.500 0.0125 **
male 1.18081 0.775689 1.522 0.1281
e401k 0.590001 0.804287 0.7336 0.4633
Explained sum of squares = 4485.49
Test statistic: LM = 2242.746588,
with p-value = P(Chi-square(4) > 2242.746588) = 0.000000
How did the LM test become so big for this model?