Dear Achim,
let me thank you for this assurance!
The sample size is too large (~4000 observations per group) to solve
this problem exactly. The error message could maybe be improved, but
the message is clear: This is too large to deal with.
However, this is not a problem. With several thousand observations,
standard normal approximations should work sufficiently well. And if
you don't believe it, then you can look at approximate solutions that
draw a sufficiently large number of permutations. Both is easily
available when using wilcox_test() in "coin" as the startup message of
"exactRankTests" suggests.
But in my dataset there are many, many tied ranks between group_1 and
group_2 and the other ones. I wanted to use the exact procedure because
I read the approximate solution would not give me exact p values in case
of tied ranks... Am I paranoid, or am I in search of an exactness
statistics cannot deliver?
Well, then I'll try permutation tests, and thank you again!
Kind regards,
David
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