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Comparative Study
. 2001 Aug 18;323(7309):391-3.
doi: 10.1136/bmj.323.7309.391.

Mann-Whitney test is not just a test of medians: differences in spread can be important

A Hart  1
Affiliations
Comparative Study

Mann-Whitney test is not just a test of medians: differences in spread can be important

A Hart. BMJ. .
No abstract available

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Figures

Figure 1
Figure 1
Two distributions with a difference in median but no difference in shape and spread
Figure 2
Figure 2
Two distributions with different medians and different shapes. The distribution with the larger median also has a greater spread
Figure 3
Figure 3
Box plots of samples of size 25 drawn from the distributions in figure 2. Vertical lines indicate the medians and boxes the interquartile range
See this image and copyright information in PMC

References

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    1. Barber JA, Thompson SG. Open access follow up for inflammatory bowel disease. Would have been better to use t test than Mann-Whitney U test. BMJ. 2000;320:1730. - PMC - PubMed

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