---
title: "Post-hoc tests (Tukey or Dunn)"
slug: "post-hoc-tests"
updated: 2026-05-27T14:47:05Z
published: 2026-05-27T14:47:05Z
canonical: "userguide.dataclassroom.com/post-hoc-tests"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://userguide.dataclassroom.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Post-hoc tests (Tukey or Dunn)

Having run an ANOVA or 2-way ANOVA test, you will have received a P-value which tells you about the likelihood of there being a significant difference between some of the groups. But it doesn't tell you **which groups differ from which** (In the T-test, there are only two groups, so the question does not arise).

This is where a Tukey's post-hoc test comes in.

A test with many namesThe test goes under a number of names. It is called Tukey's Range Test, Tukey's Honestly Significant Difference, or just Tukey's HSD.

You should see the button below the table of results:

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1623736789164.png)

And running the test gives you something like this table, where you can see each of the four groups compared with each of the other three.

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1623737158339.png)

So what does this mean? If you look at the table carefully, you'll see that **all the P-values associated with the LowCal group are significant (under 0.05)**, and this should correlate with what your eyes tell you when you look at the graph (mean and 95% confidence interval shown), i.e. that the **LowCal group is the one that is different from all the others**:

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1623736954781.png)

### Dunn's test (post-hoc for Kruskal-Wallis)

If you have run a Kruskal-Wallis test for non-parametric data (rather than an ANOVA), the post-hoc test offered will be a Dunn's test. Otherwise, details of the interface are as per Tukey above.