Visualizing Critical Values for Probability Distributions

Distribution Critical-Value Visualizer — Streamlit App (Free & Open Source)

This video walks through a lightweight Streamlit app that makes hypothesis testing visual and fast. Pick a probability distribution, set the parameters and α, get the table/critical value(s), and (optionally) enter your test statistic to see the shaded rejection region(s) plus an instant p-value and decision.

What you’ll learn

How to compute and interpret critical values (left, right, two-sided)
How test statistics map onto a distribution curve
How to read rejection regions and p-values at a glance
Differences between continuous and discrete distributions in practice

Supported distributions
Normal (Z), t, Chi-square, F, Binomial, Poisson, Exponential, Uniform

How to use

Choose a distribution and enter its parameters (e.g., df for t/χ²/F; n, p for Binomial).
Select tail type (Left / Right / Two-sided) and significance level α.
(Optional) Enter your test value/statistic to overlay on the plot.
Read the critical value(s), p-value, and Reject / Do not reject decision.
Use the diagram to visually explain your result.

Live demo & code
https://www.econistics.com/streamlit....