Re: [R] medians in Wilcoxon disagree with median function

2011-01-30 Thread Graham Smith
David, > > I am sure I am opening myself up to looking stupid, >> > > Or exposing a failure to read the help page. Well no, and of course I did read the help pages as well as several introductions on Wilcoxon before posting, but as I said in my other post it is generally not at all clear, the

Re: [R] medians in Wilcoxon disagree with median function

2011-01-30 Thread David Winsemius
On Jan 30, 2011, at 9:28 AM, Graham Smith wrote: I am sure I am opening myself up to looking stupid, Or exposing a failure to read the help page. but I have two samples with medians of 613.5 and 189 (difference in location of 424 compared to the difference suggested from the wilcoxon o

Re: [R] medians in Wilcoxon disagree with median function

2011-01-30 Thread Prof Brian Ripley
Where did you get the idea that the location estimate in a 2-sample Wilcoxon test is the difference in medians? (It is a common misconception, but not I believe to be found in R. The estimate is the median of differences, not the difference of medians: and the test is not of a difference of p

Re: [R] medians in Wilcoxon disagree with median function

2011-01-30 Thread Graham Smith
I am sure I am opening myself up to looking stupid, but I have two samples > with medians of 613.5 and 189 (difference in location of 424 compared to > the difference suggested from the Wilcoxon of 291.5) > > After a rather frustrating search, with it only explained in one of the books I found. I

[R] medians in Wilcoxon disagree with median function

2011-01-30 Thread Graham Smith
I am sure I am opening myself up to looking stupid, but I have two samples with medians of 613.5 and 189 (difference in location of 424 compared to the difference suggested from the wilcoxon of 291.5) > wilcox.test(pipwtCount,pipwdCount, conf.int=TRUE, na.rm=TRUE) Wilcoxon rank sum test da