Probability Tree Maker

Keep sequential uncertainty organized

A probability tree branches through a sequence of possible events. Each branch represents a probability conditional on reaching its starting node, while a complete path represents one combined outcome.

Use it when earlier outcomes affect later ones

Classroom problems involving draws, repeated trials, or conditional events become easier to inspect when the event order is visible. The tree also reveals missing outcomes or assumptions about independence.

Make every probability checkable

1. Define the stage order. Each level should refer to the same next event.
2. Condition on the parent. Use the probability appropriate to the path already taken.
3. Check each fork. Exhaustive, mutually exclusive branches from one node should sum to one.
4. Multiply along a path. The complete outcome uses the conditional probabilities on that route.
5. Avoid double counting. Add leaf probabilities only for distinct outcomes belonging to the requested event.

Draw the sequence and inspect the arithmetic

MyMap can arrange your event description as a branching tree with probability labels. The example uses hypothetical medical-screening rates and expected counts; it is an educational calculation, not a statement about any particular test or person.