[R] restricted permutations in permutest()?

Kay Cichini Kay.Cichini at uibk.ac.at
Tue Jan 19 15:19:45 CET 2010


hello gavin,

you are right, i didn't get into the documentation to deep and i'm also a
beginner, that's why i'm just about  to get into the logical part of the
syntax.
now, the output from perm.disp() says:

#No. of permutations: 999  
#Permutation type: free 
#Permutations are unstratified
#Mirrored permutations?: No 
#Use same permutation within strata?: No

from this i concluded that you can restrict the permutation scheme..
with permcontrol() i did the following

#with the simulated blocks from
>blocks<-factor(c(rep(1,4),rep(2,4),rep(3,4),rep(4,4),rep(5,4),rep(6,4))) 

#i did this, which should permute strata as a whole, as i understood the
documentation
>permutest(mod, permControl(strata = blocks, type = "free", permute.strata =
TRUE), pairwise=TRUE)

and the output said..

Permutations: 199  
Permutation type: free 
Permutations stratified between 'blocks'
Mirrored permutations?: No 
Use same permutation within strata?: No

so, i stratified the permutation, but i have the feeling that#s not what it
should be - to my understanding it is necessary to permute the
group-alignment of each block concordantly and i don't know if that's what
happend.. the last line of the presented output shoul be yes, i guess. the
documentation quotes that the argument for this is permute.strata=TRUE,
which i did... 

thanks a lot for your help,
kay
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