I love this! I can imagine myself using this as an ad hoc calculator, especially when I need to explain my estimates to someone unfamiliar with probability. For that purpose it might be useful if I could fill in my own labels for all the variables. So instead of "E1/E2/..." the page could literally display "Drew a black marble/drew a white marble/..." or whatever I put in.
Snapping to whole percentages might be better too. Having a displayed value of "87.23%" overstates how much control I have in choosing a specific value, given how the sliders work and how finicky per-pixel selection is.
Hey thanks for the feedback! After playing around with it more myself I agree with you about the percentages. I think ideally for more precise values it would have a manual input option, but rounding to whole values for now would be better. I also like the label changing suggestion.
A simplified version of the page for interpretation of medical test results:
https://romex91.github.io/sick-or-healthy/
This visualization was inspired by the Julia Galef video that I linked to in the opening paragraph. One thing I liked about that video is that it represents probability space as a box which, for understanding Bayes' rule, I think is much more intuitive than the circular venn-diagram approaches. Some improvements that I think this visualization offers is showing the different probabilities updating in relation to each other, generalizing to more than two events for both priors and likelihoods, and explicitly showing the discarding of conditional probabilities of unobserved events and normalization of the posteriors.