Probability Rules — Venn Diagrams
Visualize addition rule, conditional probability, and independence with interactive Venn diagrams. See P(A∪B) and P(A|B) as areas.
P.03 / PROBABILITY RULES
Probability Rules — Build Intuition with Venn Diagrams
You've got the shape of the normal. Now let's step back to the foundations — the probability rules that make all of it work. Addition, multiplication, and conditional probability visualized as overlapping areas.
Addition rule, multiplication rule, conditional probability — see them as areas before memorizing formulas.
P(A∪B) = P(A) + P(B) − P(A∩B) is just "area of two circles minus the overlap."
Conditional probability P(A|B) is "the fraction of B's circle occupied by A."
Press the Independence button to snap P(A∩B) = P(A)·P(B) — that's what independence means.
P(A|B) = P(A∩B) / P(B) , P(A∪B) = P(A) + P(B) − P(A∩B)
▶ Interactive Venn Diagram
P(A∪B)—
P(A|B)—
P(B|A)—
Independent?—