Skip to main content
Mail a PDF copy of this page to:
(Your email address will not be added to a mailing list)
Show menu

Comparison of two proportions

Next selectComparison of
Next selectproportions


Performs a Chi-squared test for the comparison of two proportions (from independent samples), expressed as a percentage.

MedCalc uses the N−1 Chi-squared test as recommended by Campbell (2007) and Richardson (2011).

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

Note that when the total number of cases is less than 20, it may be more appropriate to perform Fisher's exact test.

Required input

In the dialog box, you can enter the two proportions (expressed as percentages) and the total number of cases.

For example when the prevalence of a disease in one sample of a total of 120 patients is 80%, and the prevalence of the disease in another sample of a total of 210 patients is 70%, you will enter the following in the dialog box:

Comparison of two proportions

After you click Test, the results of the test are displayed.


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


Recommended book

Book cover

Statistics with Confidence: Confidence Intervals and Statistical Guidelines
Altman DG, Machin D, Bryant TN, Gardner MJ (Eds)

Buy from Amazon

This introduction to confidence intervals has been updated and expanded to include methods for using confidence intervals, with illustrative worked examples and extensive guidelines and checklists to help the novice. There are six new chapters on areas such as diagnostic studies and meta-analyses.