Terms of use
What is and is not allowed on the site and with its content, who holds the rights, and what the limits of liability are. Last updated: November 2026.
1. The site
Professor Stat is an English-language site of statistical calculators and research-methods guides. The site is offered to the public free of charge. Use of the site constitutes agreement to these terms; anyone who does not agree to them is asked not to use the site.
2. What is allowed
You may use the calculators and guides for study, research and professional work, including paid work. You may include in papers, articles and reports the results, tables, charts and syntax that the site produces from your data. We would appreciate a citation of the source: "Computed on the Professor Stat site".
3. What is not allowed
Without written permission from the site owner, it is not allowed: to copy, duplicate, publish or distribute the site's pages, the calculators' code or the guides, in whole or in part; to upload a copy of the site or of part of it to another address; to sell the site's content or charge for access to it; to remove the site's name or the copyright notice; to collect the site's content by automated means; or to attempt to disrupt the site's operation. A short quotation from the guides, with a citation of the source and a link to the page, is allowed.
4. Copyright
All rights in the site – the design, the calculators' code, the guides, the wording and the examples – belong to Efrat Lia Shahaf, the site owner. Open-source components and third-party data files included in the site are subject to their own licenses, as indicated where they appear.
5. Your data and privacy
The calculations run in your browser only. The data you load into the calculators are not sent to a server and are not stored by us, and they remain yours and your responsibility – including the duty to protect the participants' privacy and to follow the ethical rules that apply to your research.
Usage measurement. To know how many people use the site and which pages, we count page visits anonymously – without cookies and without identifying you – using the GoatCounter service. Those who consent to this in the window that appears on the first visit to the site are also measured using Google Analytics, a Google service that uses cookies and receives information about the use of the site, such as the pages viewed, the type of device and browser, and the estimated geographic region. We use this information only to understand how the site is used and to improve it; the use that Google makes of it is subject to its privacy policy. The data you load into the calculators are not part of the measurement and do not leave the browser.
The choice is saved in your browser, and you can change it at any time: .
6. Liability
The calculators and guides were checked carefully, but they are aids and are provided as is. The site is not a substitute for statistical consultation, professional judgment or guidance from a supervisor. Responsibility for choosing the test, checking the assumptions, interpreting the results and using them lies with the user. The site owner is not liable for damage caused by use of the site or reliance on it, and does not undertake that the site will be available at all times or free of errors. Found an error? We would be glad if you wrote to us.
7. Changes
The site is updated, and the terms may change. The binding version is the one that appears on this page, with the update date at its top.
8. Governing law and jurisdiction
These terms are governed by Israeli law, and jurisdiction in any matter concerning the site is granted to the competent courts in Tel Aviv-Jaffa.