On Feb 9, 2008 1:50 AM, <[email protected]> wrote:
<snip>
> If I want to do a likelihood ratio test of
> H_o: sigma_u = 0
> With a test statistic of LR = -2*(L(H_o)-L(H_a),
> what is the appropriate value for L(H_o)?
>
> Is it the e(ll_c) value saved in the frontier results
> (in which case e(chi2_c) is my test statistic)
Yes, it is the log likelihood for H_o: sigma_u = 0
> I thought they would be numerically equivalent (if
> sigma_u = 0, the frontier collapses to a simple
> linear regression - and the likelihoods for normal
> errors should be the same).
When simga_u = 0 and mu = 0 then the truncated normal model reduces to OLS.
Scott
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