building a regression model

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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