- Thread starter nofunsally
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- Tags distance matrices matrix response

The matrix's values are the Euclidian distances between all points (NxN, or here, 100x100).

Is it a matrix or a vector?

How is each distance distributed?

My dependent variables are Population Mean and Population Trend (slope) of a mammal. I have other independent variable measuring various aspects of habitat. I have the suspicion that these distances may be 'important' with regards to the dependent variables. I am just looking for a way or ways to do this or at least think about it.

Thank you kindly,

Cheers,

Besides, you still haven't described your problem yet. What is your model? I don't really get why the measurements are random either.

"Um, the distance are locations of the Earth". Yeah, but we are doing statistics here, so you need statistical distributions. If you had just one measurement. How would you model it?

Thanks for you reply. I know my ambitions seem obtuse. Right now, I don't have a model, I am trying to determine if there is a way I can use these distance as an independent variable. With or without it I will probably use AIC for model selection with the other variables.

The problem I am encountering is that my other variables are, mostly, demonstrating a fair amount of spatial autocorrelation. This got me thinking that maybe these 'distances' might be 'important' in the model. I just don't know how I would use them or if I can. Thanks for your help, perhaps adding them as a vector would work, I obviously need to read more about that.

I don't really get why the measurements are random either.

I really appreciate your help,

Cheers,

If you have a singe response varaible and you are firm set on using a distance matrix, then you could produce an NMDS on Euclidena distances and overlay your means in a bubble plot. However, would be inclined to first look at geographic distance and means in simple regression analyses first to determine what type of, if any relationship there is between the two varaibles. Producing a distance matrix on these geographic distances doesn't make make much ecological sense to me because in Euclidean space

sites close together will group close together same as the farther sites. We know this. However, if you had some more meaningful information about your sites (latitude, mean annual temps. rainfall etc...) and incorporate this into your analysis, it might be a better place to start.

At the moment (unless I have missed something obvious) you have a univarite study (distance vs. pop means) and you should treat it as such.

As far as the Mantel tests, the second non-Euclidean distance matrix could created from any variable by calculating the distance (difference between values of the same unit), right?

Thanks again I enjoy the discussion,

Cheers,

As far as the Mantel tests, the second non-Euclidean distance matrix could created from any variable by calculating the distance (difference between values of the same unit), right?