执行Wilcoxon测试之前是否需要缩放？

Question

我正在对我的数据进行Wilcoxon等级总和测试。这些数据是不同的单位，并在很大程度上不同。 运行测试之前是否需要输入此命令？

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

还是Wilcoxon秩和检验本身就是这样做的？

Answer 1

由于Wilcoxon是一个位置测试（R中的默认值为mu = 0），所以无法缩放，并且如果缩放数据，则会丢失真实的位置信息。

> 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