JASP Tutorial: Independent Samples T-Test Frequentist (or Classical) and Bayesian

This tutorial conducts two independent samples t-tests (one frequentist and another Bayesian) using JASP statistical software and reports the results.
Please leave and questions/comments below!
To download JASP:
jasp-stats.org...
General usage JASP: static.jaspstat...

[@Leilani1041]

This was so helpful! thank you so much Karyssa

[@anwarashek5317]

Great! elucidate

[@karyssa_]

Thank you!

[@aoifemaguire175]

Hi
I recently ran several Bayesian independent samples t tests using the informed prior vs the default prior. I understand why the same analyses using the informed prior gives a bigger Bayes factor compared to the default, but I didn’t expect the effect sizes to all be smaller (and credible intervals narrower) when using the informed prior. Does anybody know why this might be?

[@karyssa_]

It's hard to address your specific problem without seeing your analysis, but I would guess that the informed prior added information making the posterior estimation more certain in the parameter estimate (and thus credible intervals narrower). When the prior is non-informative, the posterior is much more similar to likelihood (because the posterior is a compromise between the prior and the likelihood). It's possible that the informed prior centered on a smaller effect size, causing the posterior effect size to be smaller compared to the analysis with a non-informed prior.