Nested longitudinal data

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Nested longitudinal data

arun kirshna
Hi,

I have some difficulty in figuring out whether I am doing correct or not.


A brief introduction about the work: It is a light/dark choice test
conducted in insect larvae.  The response is binary (0- present in dark
area, 1-present in light area) and the experiment is run for 15 min, so
there are 15 repeated measurements per individual larva at 1 min
intervals.  The factors which affect this study are Strain (2 levels-G
and S),  wavelength of light (4 levels-blue, green, UV, red), and
starting response at 0 min (two levels- animal present in dark-D or
light-L).  This is how I think it is nested.  Strain nested inside
Wavelength, Subject (individual) nested within strain, Starting response within subject, and time within Starting response.   The data looks like this:     

         Number              Wavelength     Strain             Subject           Startingresponse              time (min)
                1                        Red              G                   1                          L                               1
                2                        Red              G                   1                          L                               2
            ---------------------------------------------------------------------------------------------------------------
        ---------------------------------------------------------------------------------------------------------------------
              20                      
 Red              G                     1                         L                                20
               21                      Red              G                      2                        D                                1
                22                      Red               G                    2                        D                                2

            ---------------------------------------------------------------------------------------------------------------

    -----------------------------------------------------------------------------------------------------------------------
             
 40                      Red               G                      2      
                   D                             20
              
 -----------------------------------------------------------------------------------------------------------------
             ----------------------------------------------------------------------------------------------------------------
 
           121                     Green             G                  
   7                           D                             1
            122                    Green              G                    7                           D                             2
   ------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------------------------------------------
            
The model I used was:


(fm2 <-lmer(Response~Wavelength+Startingresponse+Strain+ time + (time|Subject),family=binomial, data=Behavdat))

I am not sure how to specify the nested structures within the
 model. 

Any help will be appreciated.
Thanks.
        [[alternative HTML version deleted]]


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Re: Nested longitudinal data

Bert Gunter
Wrong list. Post on r-sig-mixed-models.

-- Bert

On Mon, Apr 23, 2012 at 8:46 PM, arun <[hidden email]> wrote:

> Hi,
>
> I have some difficulty in figuring out whether I am doing correct or not.
>
>
> A brief introduction about the work: It is a light/dark choice test
> conducted in insect larvae.  The response is binary (0- present in dark
> area, 1-present in light area) and the experiment is run for 15 min, so
> there are 15 repeated measurements per individual larva at 1 min
> intervals.  The factors which affect this study are Strain (2 levels-G
> and S),  wavelength of light (4 levels-blue, green, UV, red), and
> starting response at 0 min (two levels- animal present in dark-D or
> light-L).  This is how I think it is nested.  Strain nested inside
> Wavelength, Subject (individual) nested within strain, Starting response within subject, and time within Starting response.   The data looks like this:
>
>          Number              Wavelength     Strain             Subject           Startingresponse              time (min)
>                 1                        Red              G                   1                          L                               1
>                 2                        Red              G                   1                          L                               2
>             ---------------------------------------------------------------------------------------------------------------
>         ---------------------------------------------------------------------------------------------------------------------
>               20
>  Red              G                     1                         L                                20
>                21                      Red              G                      2                        D                                1
>                 22                      Red               G                    2                        D                                2
>
>             ---------------------------------------------------------------------------------------------------------------
>
>     -----------------------------------------------------------------------------------------------------------------------
>
>  40                      Red               G                      2
>                    D                             20
>
>  -----------------------------------------------------------------------------------------------------------------
>              ----------------------------------------------------------------------------------------------------------------
>
>            121                     Green             G
>    7                           D                             1
>             122                    Green              G                    7                           D                             2
>    ------------------------------------------------------------------------------------------------------------------------
> ---------------------------------------------------------------------------------------------------------------------------
>
> The model I used was:
>
>
> (fm2 <-lmer(Response~Wavelength+Startingresponse+Strain+ time + (time|Subject),family=binomial, data=Behavdat))
>
> I am not sure how to specify the nested structures within the
>  model.
>
> Any help will be appreciated.
> Thanks.
>        [[alternative HTML version deleted]]
>
>
> ______________________________________________
> [hidden email] mailing list
> 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.
>



--

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
______________________________________________
[hidden email] mailing list
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.