[R-sig-ME] Mixed model on few individuals

[Simon POTIER]

Dear Thierry,

Thank you very much for this answer.

I will go for it and see the output of the models.

All the best,

Simon

2018-03-06 10:20 GMT+01:00 Thierry Onkelinx <thierry.onkelinx at inbo.be>:

> Dear Simon,
>
> Interesting problem. 3 individuals is too small for a random effect of
> individual see http://bbolker.github.io/mixedmodels-misc/glmmFAQ.html#
> should-i-treat-factor-xxx-as-fixed-or-random
>
> However you still have 51 trials. So that would be relevant to include as
> a random effect. The azimuth and elevation are your response variables? In
> that case you rather have temporal autocorrelation. The nlme package has
> several models for temporal autocorrelation among the residuals. The INLA
> package provides models where the random effects have temporal
> autocorrelation.
>
> Best regards,
>
>
> ir. Thierry Onkelinx
> Statisticus / Statistician
>
> Vlaamse Overheid / Government of Flanders
> INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
> FOREST
> Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
> thierry.onkelinx at inbo.be
> Havenlaan 88
> <https://maps.google.com/?q=Havenlaan+88&entry=gmail&source=g> bus 73,
> 1000 Brussel
> www.inbo.be
>
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> 2018-02-26 9:28 GMT+01:00 Simon POTIER <sim.potier at gmail.com>:
>
>> Dear all,
>>
>> First, I will try to be the most comprehensible, if not, do not hesitate
>> to
>> ask for more information.
>>
>> I am working on a project with collaborators, and I am trying to analyse
>> the data. For one question, however, I do not feel confident with my
>> method, but I do not know how I can analyse the data in a different way.
>>
>> We are working on visual fixation of a prey while hunting, with a new
>> method of high accuracy. This method is very interesting but implies that
>> we cannot use many individuals (because of different things that are not
>> of
>> interest here I think).
>>
>> My major problem here is that I have "only" 3 individuals and 51 trials
>> (almost equilibrate per individual).
>> I also have 3 different conditions (i.e. 3 types of prey). All these
>> conditions have been repeated for the 3 individuals.
>> In total, the dataset is relatively large as I have more than 6000 points
>> (large for behavioural study), but, as I wrote, with only 3 individuals.
>>
>> Regarding this type of dataset, I am wondering whether I can use mixed
>> model to compare the visual fixation according to the different
>> conditions.
>> So here are my two questions :
>>
>> 1) Can I use mixed models with only 3 individuals? If not, do you know if
>> I
>> can use another model? Or should I compare each individual independently?
>>
>> 2) My data are spatio-temporal (visual fixation in times: One Azimuth and
>> one elevation every X sec). How can I implement this autocorrelation in my
>> model?
>>
>> I am sincerely grateful if someone can be of any help. Sorry If similar
>> question has been posted before, I did not find it.
>>
>> Best regards,
>>
>> Simon Potier
>>
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>>
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>> R-sig-mixed-models at r-project.org mailing list
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>>
>
>


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Simon Potier
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