Sorry if this is a trivial question, but I couldn't find anything on it.

I am running a Dunn-test with the dunn.test-package:

dunn.test(data$climatescepticism, g = data$mediaoutlet, method = "bonferroni")

I get the following output:

data: x and group
Kruskal-Wallis chi-squared = 28.2413, df = 3, p-value = 0

                         Comparison of x by group                            
Col Mean-|
Row Mean |          1          2          3
       2 |   4.638266
         |    0.0000*
       3 |   0.166923  -4.445118
         |     1.0000    0.0000*
       4 |   2.842656  -2.566897   2.592805
         |    0.0134*     0.0308     0.0286

To report this results in my thesis I need the standardized test statistic.

Is the Z statistic in this output already standardized? And if not, how is it possible to obtain the standardized value or at least get the standard error to calculate it myself?

  • $\begingroup$ "Sorry if this is a trivial question, but I couldn't find anything on it." Perhaps try e-mailing the author at the supplied address in the documentation? $\endgroup$
    – Alexis
    Commented Dec 18, 2021 at 19:23

2 Answers 2


The $z$ test statistics are reported in the output of dunn.test, as you can see in your supplied output (e.g., 4.638266 is the $z$ statistic, and the starred 0.0000 beneath it is the $p$ value). Aside: all $z$ statistics are ‘standardized’ in that they derive from the standard normal distribution.

If your use the list=TRUE option, you will get the same numbers ($z$ statistics and $p$ values) arranged in list form also.


if you want to get the z-score, try installing the package "FSA" instead. See the image of the code below. Cheers.

enter image description here

  • 1
    $\begingroup$ –1 dunnTest in the FSA package is just a "rewrapping" of my dunn.test package and offers no additional functionality. $\endgroup$
    – Alexis
    Commented Dec 18, 2021 at 19:20

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