Hello everyone!
I'm modelling a Stochastic Cost Frontier with the command frontier.
I'm trying to find the model's best functional form by using a
Likelihood-ratio test.
My output:
********
. lrtest A B, stats
Likelihood-ratio test LR chi2(6) = 49.42
(Assumption: B nested in A) Prob > chi2 = 0.0000
-----------------------------------------------------------------------------
Model | Obs ll(null) ll(model) df AIC BIC
-------------+---------------------------------------------------------------
B | 439 . 548.5923 17 -1063.185 -993.748
A | 439 . 573.3007 23 -1100.601 -1006.658
-----------------------------------------------------------------------------
Note: N=Obs used in calculating BIC; see [R] BIC note
*********
1. Why are there no ll(null) in the statistics?
2. What do the results imply? Which model should I choose?
Thanks
Monika
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