For two matched-pair sample vectors x and y, perform a Wilcoxon signed-rank test of the null hypothesis PROB (x > y) == 1/2.
Under the null, the test statistic z approximately follows a standard normal distribution when n > 25.
Caution: This function assumes a normal distribution for z and thus is invalid for n ≤ 25.
With the optional argument string alt, the alternative of interest
can be selected. If alt is "!=" or "<>", the null
is tested against the two-sided alternative
PROB (x > y) != 1/2. If alt is ">", the one-sided
alternative PROB (x > y) > 1/2 is considered. Similarly for
"<", the one-sided alternative PROB (x > y) < 1/2 is
considered. The default is the two-sided case.
The p-value of the test is returned in pval.
If no output argument is given, the p-value of the test is displayed.
Package: statistics