Take it and use it
StatsCapybara is free to read, and it is also openly licensed. You may copy it, change it, translate it, print it, build on it and teach from it, without asking permission and at no cost. This page says what the licenses are and how to credit the source.
The short version. The teaching material is under CC BY 4.0. The code that runs the site is under the MIT license. Credit Hakan Karsilar and StatsCapybara, link back, and say if you changed something. That is all the licenses ask.
The two licenses
The site has two kinds of material, and each needs a different license. The prose, the questions and the datasets are creative and educational work, so they are under a Creative Commons license. The scripts that draw the visualizations are software, so they are under a software license.
| Part | License | What that covers |
|---|---|---|
| Content | CC BY 4.0 | Lesson prose, common questions, glossary definitions, quiz and check questions, the 100 practice problems with their worked solutions, the long-form guides, the tool-page copy, the three printable posters, the ten practice datasets, and the capybara artwork. |
| Code | MIT | The shared scripts, the stylesheet, the service worker, each lesson's inline visualization script, and the checking tools that test the numbers. |
Where the two meet, take whichever license suits your purpose.
What you may do
You may do anything with it, for any purpose, commercial or not. Some examples, all of them permitted:
- Assign lessons in a course at any institution, or embed an interactive in your own virtual learning environment.
- Print the posters, the formula sheet or a whole lesson and hand them out.
- Translate a course into another language and publish the translation.
- Copy a practice problem into an exam, or a dataset into a lab.
- Fork the whole site, strip out what you do not teach, add what you do, and run it for your own students under your own name.
There is no institutional license to sign, no seat count, no time limit and no invoice.
What you must do
Credit the source, and be clear about whether you changed it. Copy this line and adjust it:
Adapted from StatsCapybara by Hakan Karsilar, licensed under CC BY 4.0. Changes were made.
If you reproduced something unchanged, write "From" instead of "Adapted from" and drop the last sentence. For code, keep the MIT copyright notice with it. That is all MIT asks.
One thing the license does not allow: adding legal or technical restrictions that stop the next person from doing what you were just allowed to do.
Two special cases
Nine of the ten practice datasets are simulated from a fixed seed by a script in the site's repository, so they are this site's own work and come under its license. The tenth is real published data, reproduced unchanged. Facts cannot be copyrighted, but the credit for that dataset belongs to its source.
The capybara is CC BY 4.0 like everything else, so you may redraw it, recolor it and put it in your slides. What no license grants is permission to present your version as this site, or to suggest that the site endorses your work. That is a trademark matter, and Creative Commons licenses deliberately leave trademarks out.
Citing it
If the site helped a thesis, a paper or a syllabus, a citation is welcome and never required. The citation details are also in a machine-readable CITATION.cff file, and this works as plain APA:
Karsilar, H. (2026). StatsCapybara: a free, interactive statistics course for visual learners [Open educational resource]. https://statscapybara.com/
Why bother licensing something already free
Free of charge and free to reuse are different promises. A lecturer who wants to translate a lesson into Dutch or put a poster into their own handout needs the second one. Without an explicit license, ordinary copyright applies by default, and each of those uses needs permission first. Most people will not write to ask. They will close the tab, and the material goes unused by the people who wanted it.
An open license also matches what the site teaches. The courses in Methods and Ethics argue for reproducibility, transparent methods and shared materials, and it would be inconsistent to teach that while reserving all rights over the lessons.
Corrections and contributions
Corrections are the most useful contribution, especially statistical ones. The Spotted a mistake? Tell me link at the foot of every page opens an email with the page address already filled in, and no account of any kind is needed to use it.
The rule for everything here applies to contributions too: every number is checked against a published source before it goes on the site, and a suite of statistical assertions tests the routines that compute them. If you propose a change that touches a number, say how you checked it.
Questions
If you want to do something and cannot tell whether the license covers it, ask rather than guess. The answer is almost certainly yes, and I would like to hear what you are building. The footer link reaches me.
Licenses applied September 2026. Full terms: CC BY 4.0 legal code · MIT license. See also Privacy and the instructor page.