[R] HELP with GLM

[David Winsemius]

> On Jan 31, 2017, at 6:35 PM, CHIRIBOGA Xavier <xavier.chiriboga at unine.ch> wrote:
> 
> Dear colleagues,
> 
> 
> I am trying to perform GLM ..but I got some objects masked: and an error message below
> 
> 
> a <- read.table(file.choose(), h<-T)
>> head(a)
>  time treatment transinduc
> 1    1   CHA0+Db     1,0768

Do note htat transinduc came in as a factor variable, not numeric.

> 2    1   CHA0+Db     1,0706
> 3    1   CHA0+Db     1,0752
> 4    1   CHA0+Db     1,0689
> 5    1   CHA0+Db     1,1829
> 6    1    PCL+Db     1,1423
>> attach(a)
> The following objects are masked from a (pos = 12):
> 
>    time, transinduc, treatment
> 
> The following objects are masked from a (pos = 13):
> 
>    time, treatment
> 
> The following objects are masked from a (pos = 14):
> 
>    time, treatment
> 
>> summary(a)
>      time         treatment    transinduc
> Min.   :1.000   CHA0   :10   1,0488 : 6
> 1st Qu.:1.000   CHA0+Db: 9   1,0724 : 4
> Median :1.000   Db     : 9   1,0752 : 3
> Mean   :1.433   HEALTHY:15   1,0954 : 3
> 3rd Qu.:2.000   PCL    :10   1,0001 : 2
> Max.   :2.000   PCL+Db :14   1,0005 : 2
>                              (Other):47
> 
> 
> m1<-glm(transinduc~time*treatment,data=a,family="poisson")
> Error in if (any(y < 0)) stop("negative values not allowed for the 'Poisson' family") :
>  valor ausente donde TRUE/FALSE es necesario
> Adem�s: Warning message:
> In Ops.factor(y, 0) : '<' not meaningful for factors
> 
> 
> I DO NOT HAVE NEGATIVE VALUES IN MY DATASET, Do you know what is going wrong?


DO NOT USE `attach`. THAT'S PROBABLY WHAT IS WRONG.
> 
> 
> Thank you for you help,
> 
> 
> Xavier
> 
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David Winsemius
Alameda, CA, USA