[R] Help on parameters

[Ronaldo Reis Jr.]

Hi,

I have a follow analysis

Trat1 = quantitative variable
Trat2 = qualitative variable with 3 levels (A, B, C)
Trat3 = qualitative variable with 3 levels (D, E, F)
Resp = Response

I try to get the parameters to compare with zero, so I make this model:

glm(Resp~Trat1*Trat2+Trat1*Trat3-Trat1-1)

The -Trat1 is to make comparison of slope with zero.
The -1 is to make comparison os intercept with zero.

The results that I want are:

Coefficients:
             Estimate Std. Error t value Pr(>|t|)    
Trat2A        
Trat2B        
Trat2C        
Trat3D
Trat3E        
Trat3F        
Trat1:Trat2A  
Trat1:Trat2B  
Trat1:Trat2C 
Trat1:Trat3D
Trat1:Trat3E 
Trat1:Trat3F 

But I get this:

Coefficients:
             Estimate Std. Error t value Pr(>|t|)    
Trat2A        1.35333    1.00307   1.349  0.18108    
Trat2B        1.35333    1.00307   1.349  0.18108    
Trat2C        4.29333    1.00307   4.280 5.14e-05 ***
Trat3E        0.86667    1.09881   0.789  0.43260    
Trat3F        0.92000    1.09881   0.837  0.40493    
Trat1:Trat2A  0.53657    0.16166   3.319  0.00136 ** 
Trat1:Trat2B  0.53657    0.16166   3.319  0.00136 ** 
Trat1:Trat2C -0.09313    0.16166  -0.576  0.56617    
Trat1:Trat3E  0.03636    0.17709   0.205  0.83783    
Trat1:Trat3F  0.34000    0.17709   1.920  0.05843 .  

Look that the intercept and slope of Trat3D dont appear

What is the problem?

Thanks
Ronaldo
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