...sorry, i was slow to grasp that. of course it is the same as for other
stratified sampling designs where i have to care for not to mix values of
possibly very different ranges when doing a permutation test..
if i've got it right, staying with the before-after design, this should give
2^n possib
...sorry, i was somewhat slow here: of course it is the same as for other
stratified sampling designs where i have to care for not to mix values of
possibly very different ranges by the permutations..
if i've got it right, then this should give 2^n possible permutations with
the paired sampling w
Hi Kay,
I meant to make permutations within time points, i.e. strata=time, and
not within locations (strate=locations). adonis do F-tests based on
sequential sums of squares from permutations, thus the non
independence of repeated measures can have an effect on p-values
associated with terms subseq
hello peter,
thanks for replying.
if we stay with the before after design, where i only want to know whether
multivariate response changed or not, you say it's ok to restrict
permutations on pairs. but then why it does not solve the problem of
dependence?
yours,
kay
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Interesting that you ask; I was currently thinking about the same thing. Once a
reviewer required us to do a Doubly Repeated Measures ANOVA "Doubly because the
multiple variables and the repeated measures parts are both multivariate
dimensions." At the time, I did not find how to do it in R, and
Kay,
using strata (restricting permutations within time points, and not
within locations) in adonis makes some sense, given that permutation
tests assume independence. But that does not solve the problem of
dependence, but it is a good starter. If you have a before-after
control-treatment design,
dear list,
i searched though the archives and the question of repeated measure analysis
with species data was often brought up but, as far as i found, never clearly
worked out.
if i have, say two time points at wich i sampled replicated plots and thus
had replicated paired mutivariate obervation
