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
>>
>>
>>
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>>
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>> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.

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