These two functions exist in R but I don't know their differences. It seems that they only return the same p-values when calling
wilcox_test (in the coin package) with
distribution="aymptotic". For other values they return different p-values. Also
wilcox.test is always returning W=0 for my dataset, independently of the settings of its parameters:
x = c(1, 1, 1, 3, 3, 3, 3) and
y = c(4, 4, 6, 7, 7, 8, 10)
Also, when I try using different tools other than R (some available online, others as Excel add-ons), sometimes they report different p-values.
So how can I know which tool is giving the "correct" p-value?
Is there a "correct" p-value, or if a few tools give a p-value < 0.05 should I be happy? (Sometimes these tools do not offer so many parametrization possibilities like R.)
What am I missing here?