# Two-way Chi-squared test

## Description

The two-way Chi-squared test allows to test the relationship between two classification factors (e.g. gender and profession)..

This test is not performed on data in the data table, but on statistics you enter in a dialog box.

## Required input

First, select the number of different categories for the two classification factors.

Next, enter the number of cases for each pair of categories.

Optionally, you can select a Chi-squared test for trend. The Cochran-Armitage test for trend (Cochran, 1954; Armitage, 1955) provides a more powerful test than the unordered test, but this test is only applicable if your classification table has 2 columns and 3 or more rows (or 2 rows and 3 or more columns), and if the data originate from ordered categories.

## Results

The results section contains the Chi-squared value, the Degrees of Freedom and associated P-value.

If the calculated P-value is small (<0.05), then there is a statistically significant relationship between the two classifications.

## Literature

- Armitage P (1955) Tests for linear trends in proportions and frequencies. Biometrics 11:375-386.
- Cochran WG (1954) Some methods for strengthening the common chi-squared tests. Biometrics 10:417-451.

## Link

Go to Two-way Chi-squared test.