R help - Aug 2015 - glm help

Inline.

Cheers,
Bert
Bert Gunter

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
   -- Clifford Stoll


On Thu, Aug 20, 2015 at 9:06 PM, David Winsemius <dwinsemius at
comcast.net> wrote:
>
>> On Aug 19, 2015, at 8:54 AM, Joaqu?n Aldabe <joaquin.aldabe at
gmail.com> wrote:
>>
>> Dear All, I?m running a glm with poisson errors and have a doubt when
>> ploting the predicted values. One of my variables has a positive slope
in
>> the summary output, but when I plot the predicted values on the
original
>> plot it draws a line with negative slope. I appreciate your comments on
>> this and any other aspect of the analysis.
>>
>> Attached is the script and data in different formats just in case.
>
> The script in .txt format was accepted by the server. The data was
apparently not in a .txt format, so it was rejected.
>
> You made three plots, so when you reply with data using the correct format
(which is plain text and generally need to have an extension .txt so that mail
client will lable as MIME-text) , you should be more specific about which plots
are not exhibiting the expected features.
>
> I noticed you made two data-frames, ?my4s' and ?my4S'. The `my4S`
was built with `cbind` which would create a matrix (probably a character matrix)
rather than a data frame.
False. There is a data.frame method for cbind that returns a data
frame. Don't know the specifics here, though.

Cheers,
Bert


 I?m wondering you you inadvertently constructed a data-object whose
structure was different than you imagined? It might have gotten
coerced back to a dataframe with undesirable
concsequences.
>
> ?
> David.
>
>>
>> Thanks in advanced,
>>
>> Joaqu?n.
>>
>>
>> --
>> *Joaqu?n Aldabe*
>>
>> *Grupo Biodiversidad, Ambiente y Sociedad*
>> Centro Universitario de la Regi?n Este, Universidad de la Rep?blica
>> Ruta 15 (y Ruta 9), Km 28.500, Departamento de Rocha
>>
>> *Departamento de Conservaci?n*
>> Aves Uruguay
>> BirdLife International
>> Canelones 1164, Montevideo
>>
>> https://sites.google.com/site/joaquin.aldabe
>> <https://sites.google.com/site/perfilprofesionaljoaquinaldabe>
>> <glm forum
consult.txt>______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

On Thu, Aug 20, 2015 at 10:04 PM, Bert Gunter <bgunter.4567 at gmail.com>
wrote:
>> I noticed you made two data-frames, ?my4s' and ?my4S'. The
`my4S` was built with `cbind` which would create a matrix (probably a character
matrix) rather than a data frame.
>
> False. There is a data.frame method for cbind that returns a data
> frame. Don't know the specifics here, though.
>
True, but does not apply here, i.e., David is correct. cbind will
return a data frame if the first argument is a data frame. In the OP
case, the first argument was a vector and hence cbind gives a matrix,
of mode "character" if any of the inputs were character. Here's a
short demo:
> a = data.frame(a1 = 1:10)
# First argument a data frame, so the results is also a data frame 
:
> class(cbind(a, b = 11:20))
[1] "data.frame"
# First argument is a vector, so the result is a matrix:
> class(cbind(a$a1, b = 11:20))
[1] "matrix"
> mode(cbind(a$a1, b = 11:20))
[1] "numeric"
> mode(cbind(a$a1, b = letters[11:20]))
[1] "character"

Peter

Inline.

-- Bert
Bert Gunter

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
   -- Clifford Stoll


On Thu, Aug 20, 2015 at 10:47 PM, Peter Langfelder
<peter.langfelder at gmail.com> wrote:
> On Thu, Aug 20, 2015 at 10:04 PM, Bert Gunter <bgunter.4567 at
gmail.com> wrote:
>
>>> I noticed you made two data-frames, ?my4s' and ?my4S'. The
`my4S` was built with `cbind` which would create a matrix (probably a character
matrix) rather than a data frame.
>>
>> False. There is a data.frame method for cbind that returns a data
>> frame. Don't know the specifics here, though.
>>
>
> True, but does not apply here, i.e., David is correct. cbind will
> return a data frame if the first argument is a data frame. In the OP
> case, the first argument was a vector and hence cbind gives a matrix,
False again.

class(cbind(a=1:5,b=data.frame(a=letters[1:5],b=3:7)))

[1] "data.frame"

##First argument a vector, but data frame is returned. Please consult
?cbind -- especially the data frame section -- for details.

Again, I don't know the specifics here, and you and David may still
well be right for what the OP did. I am only trying to correct what
appear to me to be incorrect statements about the data.frame method of
cbind (or rbind). Apologies if I have misinterpreted.

Cheers,
Bert


> of mode "character" if any of the inputs were character.
Here's a
> short demo:
>
>> a = data.frame(a1 = 1:10)
> # First argument a data frame, so the results is also a data frame  :
>> class(cbind(a, b = 11:20))
> [1] "data.frame"
> # First argument is a vector, so the result is a matrix:
>> class(cbind(a$a1, b = 11:20))
> [1] "matrix"
>> mode(cbind(a$a1, b = 11:20))
> [1] "numeric"
>> mode(cbind(a$a1, b = letters[11:20]))
> [1] "character"
>
> Peter