[R-sig-eco] Queries on regression analysis

[Guillaume Adeux]

As mentionned by Roman, linear regression does not imply that the response
is normally distributed, rather that the residuals of the model are
normally distributed.
The choice of the distribution family should mainly be based on knowledge,
that is to say poisson/negative binomial for counts (strictly positive
integers), beta for rates/proportions (bounded between 0 and 1), binomial
for success/failures, gaussian for continuous data which can be negative or
positive, gamma for continuous positive (usually doesn't work so well in my
case).
The choice of the link is a less flexible, all families have their default
link (poisson=log, binomial=logit...). The main purpose is to linearize the
relationship between X and Y.
Hope this helps,
GA2

Le jeu. 8 août 2019 à 13:16, Chitra Baniya <cbbaniya using gmail.com> a écrit :

> We have the data of "gall_diameter" and "elevations". Our objective is to
> see how does gall diameter vary along the elevation gradient. In our case
> the elevation gradient refers to the range between 1500 to 2500 m asl with
> data collected in every 250 m interval.
> Our data did not follow normal distribution. Gall_diameter is a continuous
> dependent variable. Can we apply "glm" to see the relationship between
> gall-diameter and elevation in our case?
> How can we decide the distribution in our data and its family?
> Thank you all in advance for your help.
>
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> *Chitra Bahadur Baniya, M Sc, M Phil, PhDAssociate ProfessorCentral
> Department of BotanyTribhuvan UniversityKirtipurKathmandu, Nepal*
> orcid.org/0000-0002-8746-7601
>
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