Thanks!

. lrtest (All)(A C),stats

Likelihood-ratio test                                  LR chi2(4)  =     45.00
                                                       Prob > chi2 =    0.0000

Assumption: (All) nested in (A, C)

------------------------------------------------------------------------------
       Model |    Obs    ll(null)   ll(model)     df          AIC         BIC
-------------+----------------------------------------------------------------
         All |     21   -19.49077    47.11958      4    -86.23917   -82.06108
           A |     14   -7.845462    38.61595      4    -69.23191   -66.67568
           C |      7    12.72088    31.00136      4    -54.00272   -54.21908
------------------------------------------------------------------------------

对不起，贴重复了。

[此贴子已经被作者于2008-1-4 17:37:43编辑过]