[R] building a regression model

[Katarzyna Nurzynska]

Hi 

I am trying to build a regression model. My data looks like this: 

A B C         D                    E 
1 1 1        2.57            5 
2 0 0       1.64            3 
0 5 1      4.8                    1 
1 3 0      3.56                   168 
1 1 1      2.13                   1 
0 3 1      5                   168 
2 0 0      7.75                   28 
4 0 2     2.85                  168 
3 0 1     1.89                  6 
1 1 1    2.33                  3 
3 2 2    1.77                 168 
1 0 0    1.38                 0.04 
0 6 1     4. 11                    168 
2 2 2      2.86                 1 
3 1 1     4.11                 168 
3 0 2      3                 84 
1 1 1      2.5                  56 

where E is a response variable and A, B, C, D are predictor variables. Below are commands which I enter in R: 

str (mydata) 
mydata.lm = lm (E ~ 1, data = mydata) # to create a blank model 
add1(mydata.lm, mydata, test='F') # to add the best predictor variable to the blank model 

However at this point the message appears: 

Warning messages: 
1: In model.matrix.default(Terms, m, contrasts.arg = object$contrasts) : 
  the response appeared on the right-hand side and was dropped 
2: In model.matrix.default(Terms, m, contrasts.arg = object$contrasts) : 
  problem with term 4 in model.matrix: no columns are assigned 

What does it mean ? Could you please help ? 


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