[R-sig-eco] MANCOVA in R

[Michel Rapinski]

Thanks for the help.

What exactly is it called if it is not a MANCOVA and how does it differ
from a true MANCOVA?

Cheers,

Michel

> On Fri, 2011-11-25 at 10:47 +0100, marcelino.delacruz at upm.es wrote:
>> Hi,
>>
>> maybe adonis? e.g.,
>>
>> library(vegan)
>> adonis(Y~Lat+Lat2+Year+Lat:Year+Lat2:Year)
>>
>>
> Michel,
>
> This (adonis) does not do MANCOVA in its basic setting. Normal lm() does
> multivariate linear models when the dependent variable is a matrix. If
> it is a data.frame, you must cast it as a matrix:
>
> lm(as.matrix(Y) ~  Year*(Lat + Lat2))
>
> Old-fashioned people use name MANCOVA when a multiple linear model has
> factors and interaction terms.
>
> The tests can be found with anova() of its results and details of the
> fit with summary(). Although I said that adonis() does not do MANCOVA,
> you can get the same F-values but with permutation statistics if you use
> Euclidean distances:
>
> adonis(dist(Y) ~  Year*(Lat + Lat2))
>
> However, that should not be called as MANCOVA (because it is not
> MANCOVA).
>
> Cheers, Jari Oksanen
>
>> Con fecha 25/11/2011, "Michel Rapinski" <mrapi090 at uottawa.ca> escribió:
>>
>> >Hi,
>> >
>> >I am trying to perform an MANCOVA in R with permutation tests of
>> >significance.
>> >
>> >The model I want to test is:
>> >
>> >Y~Lat+Lat2+Year+Lat:Year+Lat2:Year
>> >
>> >Where Year is the grouping variable, while Lat and Lat2 are continuous
>> >variables representing Latitude and its square.
>> >
>> >Does anyone know how to do this in R?
>> >
>> >Thank you,
>> >
>> >Michel
>> >
>> >
>> >Michel Rapinski, MSc. Student
>> >Inst. of Plant Biology Research, Montreal Botanical Garden
>> >Université de Montréal
>> >Montréal, QC H1X 2B2
>> >Tel: 514.772-1710
>> >Fax: 514.872.9406
>> >michael.rapinski at umontreal.ca
>> >
>> >University of Ottawa
>> >mrapi090 at uottawa.ca
>> >
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