Wilcoxon Rank Sum Test

  • The Wilcoxon Rank Sum Test assumes that both our samples are independent SRSs and will give trustworthy conclusions only if this condition is met.

  • The Wilcoxon Rank Sum Test assumes that your data come from a continuous distribution.

  • The Wilcoxon Rank Sum Test is an alternative to the two-sample $t$-test when the guidelines for its use are not met (such as when the data is strongly skewed or has outliers).

Sample 1 Sample 2
Sample data goes here
(enter numbers in columns):
Null Hypothesis:$H_0:$ Sample 1 and Sample 2
come from the same distribution.
Alternative Hypothesis:$H_a$: Sample 1 has distribution
with values than Sample 2.
Level of Significance: $\alpha=$

Sample Sizes: $n_1=$$n_2=$
Sample Medians: $M_1=$ $M_2=$
$W$ statistic: $W=$
Mean of $W$ under $H_0$:$\mu_W=$
Standard Deviation of $W$ under $H_0$ (with tie correction): $\sigma_W=$
$z$ Value for Test (with continuity correction): $z=$
Critical $z$ Value: $z^{*}=$
$p$-value: $p=$