執行Wilcoxon測試之前是否需要縮放？

Question

我正在對我的數據進行Wilcoxon等級總和測試。這些數據是不同的單位，並在很大程度上不同。 運行測試之前是否需要輸入此命令？

## where x is my data frame 
scale(x, center = TRUE, scale = TRUE) 

還是Wilcoxon秩和檢驗本身就是這樣做的？

Answer 1

由於Wilcoxon是一個位置測試（R中的默認值爲mu = 0），所以無法縮放，並且如果縮放數據，則會丟失真實的位置信息。

> x <- rnorm(100,700,20) 
> 
> wilcox.test(x) # Mu = 0 

     Wilcoxon signed rank test with continuity correction 

data: x 
V = 5050, p-value < 2.2e-16 
alternative hypothesis: true location is not equal to 0 

> wilcox.test(x,mu=mean(x)) 

     Wilcoxon signed rank test with continuity correction 

data: x 
V = 2650, p-value = 0.6686 
alternative hypothesis: true location is not equal to 697.4377 

> wilcox.test(scale(x)) # Mu = 0 

     Wilcoxon signed rank test with continuity correction 

data: scale(x) 
V = 2650, p-value = 0.6686 
alternative hypothesis: true location is not equal to 0