Hi, I am trying to use the summary from the glm function as a data source. I am using the call sink(<some file>) then summary(logisticRegModel)$coefficients then sink(). The independent variables are categorical and thus there is always a baseline value for every category that is omitted from the glm output. I am interested in how to get the Z column for all of the categorical values. I don't see any row for the reference category. How can I get this Z value in the output?
Logistic Regression output baseline (reference) category
5 messages · Bert Gunter, David Winsemius, Michael Artz
The reference category is aliased with the constant term in the default contr.treatment contrasts. See ?contr.treatment , ?C, ?contrasts If you don't know what this means, you should probably consult a local statistical resource or ask about linear model contrasts at a statistical help website like stats.stackexchange.com. This list is for R programming questions. Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
On Tue, Mar 15, 2016 at 1:27 PM, Michael Artz <michaeleartz at gmail.com> wrote:
Hi,
I am trying to use the summary from the glm function as a data source. I
am using the call sink(<some file>) then
summary(logisticRegModel)$coefficients then sink(). The independent
variables are categorical and thus there is always a baseline value for
every category that is omitted from the glm output. I am interested in how
to get the Z column for all of the categorical values. I don't see any row
for the reference category. How can I get this Z value in the output?
[[alternative HTML version deleted]]
______________________________________________ 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 Mar 15, 2016, at 1:27 PM, Michael Artz <michaeleartz at gmail.com> wrote: Hi, I am trying to use the summary from the glm function as a data source. I am using the call sink(<some file>) then summary(logisticRegModel)$coefficients then sink().
Since it's a matrix you may need to locate a function that write matrices to files. I seem to remember that the MASS package has one.
The independent variables are categorical and thus there is always a baseline value for every category that is omitted from the glm output.
Well, it's not really omitted, so much as shared among all variables. For further reading in the halp pages consult: ?model.matrix ?contrasts ?contr.treatment But you probably need to supplement that with an introductory text that covers R regression defaults.
I am interested in how to get the Z column for all of the categorical values.
The Z column? You meant the "z value" column. Again, since it's a matrix you need to use column indexing with "[" summary(logisticRegModel)$coefficients[ , "z value"] Read up on the summary function for glm objects at: ?summary.glm
I don't see any row for the reference category.
What do you imagine the (Intercept) row to be doing? If you are having difficulty understanding this (which is not really an R-specific issue) there are probably already several explanations to similar questions on: http://stats.stackexchange.com/
How can I get this Z value in the output?
Asked and answered.
[[alternative HTML version deleted]]
______________________________________________ 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.
David Winsemius Alameda, CA, USA
10 days later
Hi, I have now read an introductory text on regression and I think I do understand what the intercept is doing. However, my original question is still unanswered. I understand that the intercept term is the constant that each other term is measured against. I think baseline is a good word for it. However, it does not represent any one of the x variables by itself. Is there a way in R, to extrapolate the individual x variable intercepts from the equation somehow. On Tue, Mar 15, 2016 at 8:26 PM, David Winsemius <dwinsemius at comcast.net> wrote:
On Mar 15, 2016, at 1:27 PM, Michael Artz <michaeleartz at gmail.com>
wrote:
Hi, I am trying to use the summary from the glm function as a data source.
I
am using the call sink(<some file>) then summary(logisticRegModel)$coefficients then sink().
Since it's a matrix you may need to locate a function that write matrices to files. I seem to remember that the MASS package has one.
The independent variables are categorical and thus there is always a baseline value for every category that is omitted from the glm output.
Well, it's not really omitted, so much as shared among all variables. For further reading in the halp pages consult: ?model.matrix ?contrasts ?contr.treatment But you probably need to supplement that with an introductory text that covers R regression defaults.
I am interested in how to get the Z column for all of the categorical values.
The Z column? You meant the "z value" column. Again, since it's a matrix you need to use column indexing with "[" summary(logisticRegModel)$coefficients[ , "z value"] Read up on the summary function for glm objects at: ?summary.glm
I don't see any row for the reference category.
What do you imagine the (Intercept) row to be doing? If you are having difficulty understanding this (which is not really an R-specific issue) there are probably already several explanations to similar questions on: http://stats.stackexchange.com/
How can I get this Z value in the output?
Asked and answered.
[[alternative HTML version deleted]]
______________________________________________ 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. David Winsemius Alameda, CA, USA
On Mar 25, 2016, at 10:19 PM, Michael Artz <michaeleartz at gmail.com> wrote: Hi, I have now read an introductory text on regression and I think I do understand what the intercept is doing. However, my original question is still unanswered. I understand that the intercept term is the constant that each other term is measured against. I think baseline is a good word for it. However, it does not represent any one of the x variables by itself.
It represents all of the X variables at their reference levels. There are no individual intercepts on a variable-by-variable basis. You accepted the notion of "baseline" You cannot parcel out single variable intercepts. What would they actually mean anyhow?
Is there a way in R, to extrapolate the individual x variable intercepts from the equation somehow.
If you describe the process by which that could be calculated, we might have basis for discussion, but as it is I think you still need to be studying the theory more. I don't intend any further resspones on R-help where these questions are off-topic, so you should direct any further questions to stats.stackexchange.com
On Tue, Mar 15, 2016 at 8:26 PM, David Winsemius <dwinsemius at comcast.net> wrote:
On Mar 15, 2016, at 1:27 PM, Michael Artz <michaeleartz at gmail.com>
wrote:
Hi, I am trying to use the summary from the glm function as a data source.
I
am using the call sink(<some file>) then summary(logisticRegModel)$coefficients then sink().
Since it's a matrix you may need to locate a function that write matrices to files. I seem to remember that the MASS package has one.
The independent variables are categorical and thus there is always a baseline value for every category that is omitted from the glm output.
Well, it's not really omitted, so much as shared among all variables. For further reading in the halp pages consult: ?model.matrix ?contrasts ?contr.treatment But you probably need to supplement that with an introductory text that covers R regression defaults.
I am interested in how to get the Z column for all of the categorical values.
The Z column? You meant the "z value" column. Again, since it's a matrix you need to use column indexing with "[" summary(logisticRegModel)$coefficients[ , "z value"] Read up on the summary function for glm objects at: ?summary.glm
I don't see any row for the reference category.
What do you imagine the (Intercept) row to be doing? If you are having difficulty understanding this (which is not really an R-specific issue) there are probably already several explanations to similar questions on: http://stats.stackexchange.com/
How can I get this Z value in the output?
Asked and answered.
David Winsemius Alameda, CA, USA