Dear all,
I need help with this:
The Wilcoxon signed rank test statistic is calculated as:
W = å Zi Ri
where Zi, i = 1, 2, . . ., n, is defined as
Zi, = 1 if Yi -M0 > 0
= 0 if Yi - M0 < 0
and Ri is the ordered rank of an absolute value | Yi - M0 |.
Could someone help me in showing that under the null hypothesis
Var (W) = {n(n+1)(2n+1)}/ 24
|