[R] factors in probit regression

[garciap]

Hi to all of you,

I'm fitting an full factorial probit model from an experiment, and I've the
independent variables as factors. The model is as follows:


fit16<-glm(Sube ~ as.factor(CE)*as.factor(CEBO)*as.factor(Luz),
family=binomial(link="probit"), data=experimento)

but, when I took a look to the results I've obtained the following:

glm(formula = Sube ~ CE * CEBO * Luz, family = binomial(link = "probit"), 
    data = experimento)

Deviance Residuals: 
       Min          1Q      Median          3Q         Max  
-1.651e-06  -1.651e-06   1.651e-06   1.651e-06   1.651e-06  

Coefficients: (3 not defined because of singularities)
                                            Estimate Std. Error z value
Pr(>|z|)
(Intercept)                                6.991e+00  3.699e+04       0       
1
CEexperimental                             5.357e-09  4.775e+04       0       
1
CENO                                      -1.398e+01  4.320e+04       0       
1
CEBOcombinado                              4.948e-26  4.637e+04       0       
1
CEBOolor                                   1.183e-25  4.446e+04       0       
1
CEBOvisual                                 7.842e-26  5.650e+04       0       
1
Luzoscuridad                               3.383e-26  4.637e+04       0       
1
CEexperimental:CEBOcombinado              -6.227e-26  6.656e+04       0       
1
CENO:CEBOcombinado                        -3.758e-26  5.540e+04       0       
1
CEexperimental:CEBOolor                   -2.611e-25  6.865e+04       0       
1
CENO:CEBOolor                             -5.252e-26  5.620e+04       0       
1
CEexperimental:CEBOvisual                 -2.786e-09  7.700e+04       0       
1
CENO:CEBOvisual                            8.169e-15  6.334e+04       0       
1
CEexperimental:Luzoscuridad               -1.703e-25  6.304e+04       0       
1
CENO:Luzoscuridad                         -1.672e-28  6.117e+04       0       
1
CEBOcombinado:Luzoscuridad                 1.028e-26  5.950e+04       0       
1
CEBOolor:Luzoscuridad                      9.212e-27  6.207e+04       0       
1
CEBOvisual:Luzoscuridad                           NA         NA      NA      
NA
CEexperimental:CEBOcombinado:Luzoscuridad  9.783e-26  8.744e+04       0       
1
CENO:CEBOcombinado:Luzoscuridad           -2.948e-26  7.959e+04       0       
1
CEexperimental:CEBOolor:Luzoscuridad       1.573e-25  9.005e+04       0       
1
CENO:CEBOolor:Luzoscuridad                -2.111e-26  8.208e+04       0       
1
CEexperimental:CEBOvisual:Luzoscuridad            NA         NA      NA      
NA
CENO:CEBOvisual:Luzoscuridad                      NA         NA      NA      
NA

(Dispersion parameter for binomial family taken to be 1)

    Null deviance: 2.0853e+02  on 150  degrees of freedom
Residual deviance: 4.1146e-10  on 130  degrees of freedom
AIC: 42


Well, there are too many levels of the original factors lacking in this
table. As an example, the factor CE has three levels (Undefined, Control,
Experimental), but in the table there are only two of them (NO=undefined,
Experimental=Experimental). I need to check the complete result, how can I
obtain the effects for the remaining levels of the factors?

Thanks,

Pablo

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