Wilcoxon Rank-Sum Test Calculator

Your details

Enter the observations for the first group, separated by commas or spaces.
Enter the observations for the second group, separated by commas or spaces.
Two-tailed tests for any difference; one-tailed tests for a specific direction.
The threshold below which you will reject the null hypothesis.
P-valueMarginal (0.05 <= p < 0.10)
0.0578

Probability of observing a test statistic this extreme if H0 is true

W statistic (rank sum)31
U statistic (Mann-Whitney)3
Z-score-1.8974
Effect size r0.507
n (Group 1)7
n (Group 2)7
SignificantNo
-1.897497.1% above · Z-score

No statistically significant difference (p = 0.0578, alpha = 0.05).

  • Group 1 (n = 7) rank sum W = 31.00; Mann-Whitney U = 3.00.
  • The standardised z-score is -1.8974 (two-tailed test with continuity correction).
  • Effect size r = 0.507, which is large by conventional benchmarks (0.1 / 0.3 / 0.5).
  • Failing to reject H0 does not prove the groups are identical; it may reflect low power due to small sample size.

Next stepConsider whether the study was sufficiently powered; a post-hoc power analysis may help interpret a non-significant result.

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