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Chi-squared test

Next selectChi-squared test


Allows to test the statistical significance of differences in a classification system (one-way classification) or the relationship between two classification systems (two-way classification).

To perform this Chi-squared test, you must already have the data classified in a frequency table (this test is not performed on the raw data).

A frequency table shows the number of cases that belong simultaneously to two or more distinct categories, e.g. patients cross-classified according to both gender and age group.

Required input

The data of the contingence table have to be entered in the table in the dialog form. Either a one-way classification can be used (occupying one single row or one single column), or a two-way classification table up to a 6 x 9 table.

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.

Dialog box for Chi-squared test


MedCalc calculates the expected frequencies for every cell in the table, and the following results are displayed:

In the Comment input field you can enter a comment or conclusion that will be included on the printed report.

Small expected frequencies

With regards to the reliability of the test in the presence of small expected frequencies, see Frequency table & Chi-squared test.


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