R Questions

[Professor Andy Field]

Use this to post questions specifically about R

[Anonymous]

Hi Andy, 

I was wondering if you had any experience with running perMANOVA’s in R using the package vegan (adonis function)? 

I am working with several explanatory variables and many clinical biochemistry/hematological response variables (all continuous, non-normally distributed).

My explanatory variables are: ID (29 levels), Treatment (2 levels),  Sex (2 levels) and  Exposure/Time (11 levels) – repeat exposure  

I am interested in (1) whether the response variable changes over time with repeated exposure and (2) whether the 2 treatment groups are significantly different from each other and whether this effect varies with time.

I think I understand how to calculate the within subject (ID) variation:

adonis(bio~ biochem12$Treatment*biochem12$EXPOSURE + biochem12$ID, strata=biochem12$ID, permutations=999, method=”euclidean”)

But I don’t know how to calculate the between subject variation maintaining that repeated measure. 

Any help would be greatly appreciated! 

Elizabeth

[Author]

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