Weather Picnic Probability Tree

Weather picnic probability tree

This probability tree models a plan that changes with the weather. It first separates the possible weather conditions, then assigns different chances to cancelling or holding the picnic after each condition. That second set of probabilities is conditional: the chance of cancelling is higher when it rains. The tree makes this dependence easier to read than a sentence or a table. It can be adapted for contingency planning, weather-sensitive events, or classroom exercises in conditional probability. To calculate a final outcome, multiply the branch probabilities from the first event through the second event. It gives readers a concise reference they can reuse when discussing the result with colleagues.

Type Arbre de décisionNorme Howard-Raiffa / CART-sklearn / taxonomyMoteur schematex-decisiontreeMis à jour 24/09/2026

La demande

“A probability tree for tomorrow's weather: Rain or No rain, then whether a picnic is cancelled or held, with cancellation probabilities 0.8 after rain and 0.1 after no rain.”

Essayez ensuiteAdd a sunny branch under no rainShow the probability of holding the picnic outside

Ce que contient ce dessin

Comprenez les décisions qui le sous-tendent.

01Weather split

Start with rain versus no rain.

02Conditional response

Use a different picnic decision after each forecast.

03Outcome labels

Name the resulting plan clearly.

Use when a later event depends on an earlier condition.

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FAQ

Questions fréquentes

Why do the second probabilities differ?

They describe the picnic decision conditional on the weather.

Can a tree show dependent events?

Yes. Give each preceding branch its own later probabilities.

How are final probabilities calculated?

Multiply the probabilities along the relevant path.