## What does Dunn test tell you?

Dunn’s Test performs pairwise comparisons between each independent group and tells you which groups are statistically significantly different at some level of α. For example, suppose a researcher wants to know whether three different drugs have different effects on back pain.

## What is Kruskal-Wallis test in SPSS?

The Kruskal-Wallis H test (sometimes also called the “one-way ANOVA on ranks”) is a rank-based nonparametric test that can be used to determine if there are statistically significant differences between two or more groups of an independent variable on a continuous or ordinal dependent variable.

**What is multiple comparisons in statistics?**

In statistics, the multiple comparisons, multiplicity or multiple testing problem occurs when one considers a set of statistical inferences simultaneously or infers a subset of parameters selected based on the observed values. The more inferences are made, the more likely erroneous inferences become.

### What does P value in Kruskal-Wallis test mean?

If the p-value is less than or equal to the significance level, you reject the null hypothesis and conclude that not all the group medians are equal. If the p-value is greater than the significance level, you do not have enough evidence to reject the null hypothesis that the group medians are all equal.

### Is Tukey test Parametric?

In statistics, the Siegel–Tukey test, named after Sidney Siegel and John Tukey, is a non-parametric test which may be applied to data measured at least on an ordinal scale. The test is used to determine if one of two groups of data tends to have more widely dispersed values than the other.

**Where in SPSS would you find the option for conducting a Kruskal Wallis test?**

Carrying out the Kruskal-Wallis test Select: Analyze → Nonparametric Tests → Independent samples In the Fields tab, move the dependent variable to the ‘Test Field’ box and the grouping factor to the ‘Groups’ box.

#### What is the recommended test for post hoc comparisons Kruskal Wallis test?

Anyhow if you think that the kruskal test is appropriate to your data you can use Dunn test as post hoc test. Using ranks in the ANOVA F test takes into account the relative levels, and it compares the mean ranks. In this sense, it combines the best features of the Kruskal Wallis Test with the ANOVA F test.

#### When to use Dunn’s test for multiple comparisons?

Dunn’s Test for Multiple Comparisons A Kruskal-Wallis test is used to determine whether or not there is a statistically significant difference between the medians of three or more independent groups. It is considered to be the non-parametric equivalent of the One-Way ANOVA.

**Do you have to do Dunn’s test by hand?**

You will likely never have to perform Dunn’s Test by hand since it can be performed using statistical software (like R, Python, Stata, SPSS, etc.) but the formula to calculate the z-test statistic for the difference between two groups is:

## How is the Dunn’s test used in statology?

Following this, the researcher could then perform Dunn’s Test to determine which drugs produce statistically significant effects.

## Is there a way to control the error rate of multiple comparisons?

Whenever we make multiple comparisons at once, it’s important that we control the family-wise error rate. One way to do so is to adjust the p-values that results from the multiple comparisons. There are several ways to adjust the p-values, but the two most common adjustment methods are: