I am trying to duplicate a Wilcoxon signed-rank test example in this Wikipedia post using R.
The data is as follows:
after = c(125, 115, 130, 140, 140, 115, 140, 125, 140, 135) before = c(110, 122, 125, 120, 140, 124, 123, 137, 135, 145) sgn = sign(after-before) abs = abs(after - before) d = data.frame(after,before,sgn,abs) d$rank = rank(replace(abs,abs==0,NA), na='keep') d$multi = d$sgn * d$rank (W=abs(sum(d$multi, na.rm = T))) W = 9
However, the test statistic value that R produces (undoubtedly due to some mistake that I am making in setting up the function or interpreting the output) is:
wilcox.test(d$before,d$after, paired = T, alternative = "two.sided", correct=F) Wilcoxon signed rank test data: d$before and d$after V = 18, p-value = 0.5936 alternative hypothesis: true location shift is not equal to 0
V=18) is different from the
9 value in the Wikipedia post.
What am I missing?