You need to read up on the Wilcoxon signed-rank test and the output from wilcox.test!!!
The confidence interval is of the difference of medians, which can certainly be negative. In fact, your estimate is -33, and the confidence interval is (-68, 0) which is reasonable. The value of W is a positive number, in general, and isn't restricted to [0,1] Abhijit > > On 3/14/2011 11:07 AM, taby gathoni wrote: >> my output is as follows: >> wilcox.test(main_samp$SCORE~main_samp$GENDER, conf.int = TRUE) >> >> Wilcoxon rank sum test with continuity correction >> >> data: main_samp$SCORE by main_samp$GENDER >> W = 2780.5, p-value = 0.04829 >> alternative hypothesis: true location shift is not equal to 0 >> 95 percent confidence interval: >> -6.800005e+01 -2.056837e-05 >> sample estimates: >> difference in location >> -33.00003 >> result of W seems suspicious since i expect the result to be between 0 and >> 1. >> >> and the confidence intervals are also -ves what could be the challenge? >> Thanks Taby >> >> >> >> >> >> >> >> >> [[alternative HTML version deleted]] >> >> >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
