[R] V-value in the wilcox.test resp. wilcox.exact

[Peter Dalgaard BSA]

Jan Malte Wiener <jan.wiener at tuebingen.mpg.de> writes:

> the way i understand the wilcox.test (or wilcox.exact) the V-value
> represents the summed up ranks of either the positive or negative
> differences, whichever sum is BIGGER.
> 
> to actually look up the p-value in a table (and to quote it in a
> publication) i need the T value, which to my understanding is the
> summed up ranks of either the positive or negative differences,
> whichever sum is SMALLER.
> 
> so i guess my question is: how do i get the T-value

At least for wilcox.test, V is the sum of the *positive* ranks. The
sum of the negative ranks can be obtained by switching the sign on x
and mu. 

In the absence of ties and exact zeros, the two rank sums add up to
sum(1:N) == N*(N+1)/2

If ties are present, standard tables are wrong anyway...

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._