🎯 Conditional Probability and Independence Explained
A 3D scatter of sample-space outcomes inside two overlapping event regions: reshape P(A), P(B) and their dependence, then zoom into B to see conditional probability P(A|B) emerge live.
A 3D scatter of sample-space outcomes sits beneath two overlapping event discs, A and B. Reshaping their size and overlap — and zooming into B — turns conditional probability and independence from formulas into something you can literally count and watch shrink.
🔬 What It Demonstrates
Each dot is an outcome; a region's measured probability is just the fraction of dots inside it. P(A∩B) versus P(A)×P(B) tells you whether A and B are independent, and conditioning on B — shrinking every point outside it — makes P(A|B) visible as the share of B that's also A.
🎮 How to Use
Set P(A) and P(B) to resize the two discs, then drag Dependence from −1 (mutually exclusive) through 0 (independent) to +1 (nested). Toggle "Condition on B" to zoom the picture down to the world where B has already happened.
💡 Did You Know?
Independence is a numerical coincidence of a particular pair of probabilities, not a promise about cause and effect — two causally linked events can still satisfy P(A∩B)=P(A)P(B) for one specific setting, then stop being independent the moment either probability changes.
A 3D scatter of sample-space outcomes inside two overlapping event regions: reshape P(A), P(B) and their dependence, then zoom into B to see conditional probability P(A|B) emerge live.
3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install