# Web apps for visualization of probability distributions

I am looking for a tool to demonstrate how the shapes of some basic probability distributions (binomial, hypergeometric, Poisson, exponential and normal) change as a function of their parameters.

I have previously used Matlab's disttool, but I find this cumbersome and visually messy. I could of course make an R script, but for pedagogical reasons I would prefer something with sliders – ideally something the students could play with themselves in their browsers.

I found a Shiny app by Matthew Leonawicz that seemed to be what I'm looking for, but all links to it appear to be dead. The others I have found are all missing the hypergeometric and Poisson distributions.

• David Kahle wrote such an applet: see ww2.amstat.org/publications/jse/v22n2/kahle.pdf. It seems to be no longer available; you might want to contact him about any current or newer versions.
– whuber
Feb 3 '20 at 14:48

I finally found out (via this README file) that the mentioned Shiny app by Matthew Leonawicz can be run locally in R with

install.packages("devtools")
devtools::install_github("leonawicz/snapapps")
library(snapapps)
snapp("rv4")


(The description for accessing it online does not work, however.)

I also liked this "Distribution calculator", which is online, although it is missing many probability distributions.