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question about a GAM model

4 messages · Bansal, Udita, Ben Bolker, dani

Original
Bansal, Udita
# 
Hi Dani,

I don?t know much about GAM but I know you can look at the plots for fitted model results to check if there is any curvature. You can use the following code:

par(mfrow = c(1,3))
plot(GAMmodel)

Bests
Udita
On 28/08/18, 1:58 AM, "R-sig-mixed-models on behalf of dani" <r-sig-mixed-models-bounces at r-project.org on behalf of orchidn at live.com> wrote:
Hi everyone,
    
    
    I have a question about a GAM model where I included three non-parametric terms. I obtained the results below. can I conclude that the associations were in fact linear and run a final GLM model without including splines? To me it seems unnecessary to include splines in the final model. How should I report these results?
    
    
    # Approximate significance of smooth terms:
    #                 edf Ref.df Chi.sq p-value
    # s(x1)      1.61   2.01   1.17   0.550
    # s(x2)      1.00   1.00   0.00   0.955
    # s(x3)      1.00   1.00   4.61   0.032 *
    
    Thank you very much,
    Dani
    
    
    
    
    
    
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Ben Bolker
# 
Don't forget to run k.check() on your model to see if you specified a
large enough basis dimension  to start with ...
On 2018-08-28 05:51 AM, Bansal, Udita wrote:
1 day later
dani
# 
Thank you very much Udita and Dr. Bolker for your responses.

It is still not clear to me how should I proceed. Would anyone else be able help with this issue,?

Best regards,

Dani


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dani
# 
Hello everyone,


I was wondering if anyone can help me calculate standardized regression coefficients from a GAM model.

I have some dummy and some continuous covariates in my GAM model. I know I could standardize only the continuous covariates and re-run the model to get the standardized coefficients. Can anyone help with some R code to create the standardized coefficients after obtaining a GAM model based on unstandardized coefficients?


Also, on a separate note, what do I do with the dummy covariates - should I just include them as they are in the model with standardized variables? I do not see how I can standardize dummy variables.


Thank you!

Best,

Dani