Data · Statistics · AI · Machine Learning
Learn quantitative thinking through interactive stories.
Probastack teaches by discovery: play with the idea, make a prediction, run the simulation, and feel the concept click before anyone hands you a formula.
Featured stories
Short, memorable, hands-on experiences.
The Monty Hall Trap
Three doors, one car. The host opens a goat. Should you switch?
Explore →The Birthday Paradox
In a room of just 23 people, it's a coin-flip that two share a birthday.
Explore →Is It Real, or Just Luck?
Maria swears her smiley-face receipts earn bigger tips. Sam says it's a fluke. Settle it — by shuffling.
Explore →How ChatGPT Reads a Sentence
AI doesn't see words the way you do — it sees puzzle pieces called tokens. Watch your text shatter.
Explore →Teach a Line to Predict
Drag a straight line through the dots to predict exam scores. Congratulations — you just did machine learning.
Explore →When Averages Lie
One treatment beats the other for small stones AND for large stones — yet loses overall. Same numbers. Watch it flip.
Explore →The Test That Cried Wolf
A test that's right 99% of the time says you're sick. Most people who hear that are perfectly fine. Here's the trick your gut keeps missing.
Explore →Browse by category
A growing map of quantitative ideas. More stories landing in each.
Statistics
Probability, inference, and the intuitions behind the math.
Experimentation
A/B testing, causal inference, and trustworthy experiments.
Machine Learning
From linear regression to gradient boosting, built up by intuition.
AI & LLMs
Tokens, embeddings, attention, and how modern AI actually works.
Analytics
Funnels, retention, cohorts, and the metrics that matter.