# Median test

This procedure is available in both the Analyse-it Standard and the Analyse-it Method Evaluation edition

Median test is a non-parametric test for a difference in central location (median) between two or more independent samples.

The requirements of the test are:

- Two or more independent samples measured on an ordinal or continuous scale.
- Samples need not be normal and need not have similar shape distributions.

## Arranging the dataset

Data in existing Excel worksheets can be used and should be arranged in a List dataset layout or Table dataset layout. The dataset must contain a continuous scale variable and a nominal/ordinal scale variable containing two or more independent groups.

When entering new data we recommend using New Dataset to create a new **2 variables (1 categorical)** dataset ready for data entry.

**Using the test**

To start the test:

- Excel 2007:

Select any cell in the range containing the dataset to analyse, then click**Compare Groups**on the**Analyse-it**tab, then click**M****edian**. - If the dataset is arranged using the table layout:

Tick samples to compare in**Variable - Groups**.If the dataset is arranged using the list layout:

Click**Variable**to select the dependent variable and click**Factor**to select the independent variable containing the groups to compare. - Click
**OK**to run the test.

Excel 97, 2000, 2002 & 2003:

Select any cell in the range containing the dataset to analyse, then click **Analyse **on the **Analyse-it **toolbar, click **Compare Groups** then click **Median**.

The report shows the number of observations analysed, and, if applicable, how many missing values were excluded. Since the test classifies the observations relative to the combined median, the combined median and the number of observations above and below are shown.

The hypothesis test is shown. The *p*-value is the probability of rejecting the null hypothesis, that the samples have the same median, when it is in fact true. A significant p-value implies that at least two samples have different medians.

**METHOD** The *p*-value is calculated using the Fisher exact test when there are two samples, otherwise the Chi-square test is used (see [1] or [2]).

## Further reading & references

- Handbook of Parametric and Nonparametric Statistical Procedures (3rd edition)

David J. Sheskin, ISBN 1-58488-440-1 2003; 517. - Practical Non-parametric Statistics (3rd edition)

Conover W.J. ISBN 0-471-16068-7 1999; 218-226.

- Welcome
- Getting started
- What's new in this version
- Installing Analyse-it
- Starting Analyse-it
- Defining Datasets
- Setting Variable properties
- Running a statistical test
- Working with analysis reports
- Analyse-it Standard edition
- Describe
- Compare groups
- Summary statistics, Box/Dot/Mean plots
- Test Difference in Location
- Independent t-test
- Mann-Whitney test
- 1-way ANOVA
- 2-way ANOVA
- Kruskal-Wallis test
- Median test
- Test Difference in Dispersion
- Test Difference in Proportion
- Compare pairs
- Correlation
- Agreement
- Regression
- Analyse-it Method Evaluation edition
- Citing Analyse-it
- Contact us
- About us