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X matrix deemed to be singular and cbind

Bert Gunter 
Soumitro:

Have you read "An Introduction to R." If not, do so, as some of your
confusion appears related to basic concepts (e.g. of factors)
explained there.

1. Presumably your categorical variables are factors, not character.
If so, when you cbind() them, you cbind their integer codes, yielding
numerical variables. This produces an in incorrect design matrix in
fitting -- 1 df per categorical variable instead of 1 less than the
number of levels. Also see ?cbind.

2. Produces the correct design matrix, but you are overfitting,
presumably because of many different levels for your categorical
variables. I suggest you consult with a local statistician to decide
how best to handle this, as you seem to be out of your depth with
regard to model fitting.

... unless I have misunderstood, of course.

Cheers,
Bert
On Fri, Jul 26, 2013 at 7:55 AM, Soumitro Dey <soumitrodey1 at gmail.com> wrote:

  
    

      
      
    

  


  


  


  
  

    

  

    
      
    
    
Thread (3 messages)

  

  

    
            
        Soumitro Dey
        
        X matrix deemed to be singular and cbind
      
      Jul 26
    
    
      
            
        Bert Gunter
        
        X matrix deemed to be singular and cbind
      
      Jul 26
    
    
      
            
        Soumitro Dey
        
        X matrix deemed to be singular and cbind
      
      Jul 26