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Re: st: unexplainable probit results


From   Maarten buis <maartenbuis@yahoo.co.uk>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: unexplainable probit results
Date   Fri, 11 Jul 2008 10:33:47 +0100 (BST)

With only 43 observations I would add more than 1 covariate, maybe two
if the data is very very well behaved. Also note the note at the bottom
that 40 observations have been completely determined by your covariates
and are thus not used in your likelyhood, leaving only 3
observations... No wonder you get weird results.

-- Maarten

--- Karen Barroga <kbarroga@yahoo.com> wrote:

> Hi,
> 
> I run my variable using probit and got the results below. How come
> there are no/missing results (dots) for some variables and yet when I
> run these variables with no results, I get results?
> 
> ---------
> 
> . probit a_w_wt age schyr ricefyr axsta axsc frel8d erel8d owner_dum
> sumwsdsyield_t sumincome fsizesum Rizal_dum member_dum cx1wwt cx2wwt
> co1wwt co2wwt cbwwt obwwt ru1wwt ru2wwt pr1wwt pr2wwt tr1e_wwt
> tr2c_wwt tr3a_wwt tr4y_wwt
> 
> Iteration 0:   log likelihood =  -20.65889
> Iteration 1:   log likelihood = -7.8035532
> Iteration 2:   log likelihood = -3.6455341
> Iteration 3:   log likelihood = -.95822287
> Iteration 4:   log likelihood = -.25576662
> Iteration 5:   log likelihood = -.07527036
> Iteration 6:   log likelihood = -.02337521
> Iteration 7:   log likelihood = -.00750029
> Iteration 8:   log likelihood = -.00245924
> Iteration 9:   log likelihood = -.00081897
> Iteration 10:  log likelihood =   -.000276
> Iteration 11:  log likelihood = -.00009389
> Iteration 12:  log likelihood = -.00003219
> Iteration 13:  log likelihood =  -.0000111
> Iteration 14:  log likelihood = -3.850e-06
> Iteration 15:  log likelihood = -1.341e-06
> Iteration 16:  log likelihood = -4.689e-07
> Iteration 17:  log likelihood = -1.638e-07
> Iteration 18:  log likelihood = -5.265e-08
> Iteration 19:  log likelihood = -4.800e-08
> Iteration 20:  log likelihood = -7.592e-09
> Iteration 21:  log likelihood = -6.152e-09
> Iteration 22:  log likelihood = -5.077e-09
> Iteration 23:  log likelihood = -5.074e-09  (backed up)
> Iteration 24:  log likelihood = -5.073e-09  (backed up)
> 
> Probit regression                                 Number of obs   =  
>       43
>                                                   LR chi2(27)     =  
>    41.32
>                                                   Prob > chi2     =  
>   0.0384
> Log likelihood = -5.073e-09                       Pseudo R2       =  
>   1.0000
> 
>
------------------------------------------------------------------------------
>       a_w_wt |      Coef.   Std. Err.      z    P>|z|     [95% Conf.
> Interval]
>
-------------+----------------------------------------------------------------
>          age |  -.3867675          .        .       .            .   
>        .
>        schyr |   1.086169          .        .       .            .   
>        .
>      ricefyr |   .3800124          .        .       .            .   
>        .
>        axsta |  -5.547729          .        .       .            .   
>        .
>         axsc |   12.72164          .        .       .            .   
>        .
>       frel8d |  -9.253356          .        .       .            .   
>        .
>       erel8d |     12.346          .        .       .            .   
>        .
>    owner_dum |  -3.629787          .        .       .            .   
>        .
> sumwsdsyie~t |    1.31215          .        .       .            .   
>        .
>    sumincome |  -.0534748   76.72575    -0.00   0.999    -150.4332   
> 150.3262
>     fsizesum |   1.128914          .        .       .            .   
>        .
>    Rizal_dum |    2.55781          .        .       .            .   
>        .
>   member_dum |   3.753627          .        .       .            .   
>        .
>       cx1wwt |  -1.092271          .        .       .            .   
>        .
>       cx2wwt |   1.702984          .        .       .            .   
>        .
>       co1wwt |  -1.846226          .        .       .            .   
>        .
>       co2wwt |  -.0006998          .        .       .            .   
>        .
>        cbwwt |   2.786398          .        .       .            .   
>        .
>        obwwt |   -2.59865          .        .       .            .   
>        .
>       ru1wwt |  -3.898595          .        .       .            .   
>        .
>       ru2wwt |  -3.928283          .        .       .            .   
>        .
>       pr1wwt |  -9.655389          .        .       .            .   
>        .
>       pr2wwt |    .829331          .        .       .            .   
>        .
>     tr1e_wwt |    2.00484          .        .       .            .   
>        .
>     tr2c_wwt |    .010138   90.12691     0.00   1.000    -176.6354   
> 176.6556
>     tr3a_wwt |   .0006733   10.95916     0.00   1.000    -21.47889   
> 21.48023
>     tr4y_wwt |   1.028878          .        .       .            .   
>        .
>        _cons |  -9.091063          .        .       .            .   
>        .
>
------------------------------------------------------------------------------
> Note: 6 failures and 34 successes completely determined.
> 
> 
> 
>       
> *
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> 


-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands

visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


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