[R] Wilcoxon V = 0
Peter Ehlers
ehlers at ucalgary.ca
Wed Jul 25 06:13:54 CEST 2012
On 2012-07-24 14:36, Naomikb wrote:
> I am running a pairwise wilcoxon signed rank test, and I am not sure how to
> interpret the result. I would like to see if there is a difference between
> the values in conditions a and b. It doesn't seem possible to have a V = 0,
> but a significant p value. Am I doing something wrong?
Not understanding the test?
V is the sum of the ranks[*] of those pairs for which a$x > b$x;
there are none, so V = 0. You can check the p-value with the
[dp]signedrank() function.
[*] ranks of absolute differences.
Peter Ehlers
>
> The command I used is this:
> wilcox.test(x=a$x,y=b$x,paired=TRUE)
>
>
> The output looks like this:
> Wilcoxon signed rank test
>
> data: a$x and b$x
> V = 0, p-value = 0.0009766
> alternative hypothesis: true location shift is not equal to 0
>
> The raw data is here:
>
> a
> participant condition x
> 34 1 fused.mu.control 315.5677
> 35 2 fused.mu.control 516.8781
> 36 3 fused.mu.control 362.8108
> 37 4 fused.mu.control 482.6022
> 38 5 fused.mu.control 423.6593
> 39 6 fused.mu.control 404.9358
> 40 8 fused.mu.control 342.7314
> 41 9 fused.mu.control 466.7561
> 42 10 fused.mu.control 467.5002
> 43 11 fused.mu.control 434.0221
> 44 12 fused.mu.control 480.2990
>
>
> b
> participant condition x
> 45 1 fused.multi 373.0648
> 46 2 fused.multi 517.5159
> 47 3 fused.multi 390.2658
> 48 4 fused.multi 497.2303
> 49 5 fused.multi 519.7867
> 50 6 fused.multi 499.7950
> 51 8 fused.multi 345.8077
> 52 9 fused.multi 479.1607
> 53 10 fused.multi 539.5856
> 54 11 fused.multi 446.9569
> 55 12 fused.multi 569.5171
>
>
>
>
> --
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