[R] building a regression model

[Bert Gunter]

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-- Bert

On Sat, Jan 5, 2013 at 3:06 AM, Katarzyna Nurzynska
<paxkn at nottingham.ac.uk> wrote:
> 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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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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