Calculadora de Probabilidade Online Grátis
Single and compound event probability (AND/OR) with odds, complement and expected value
The Probability Calculator handles single event probability, compound events (AND/OR), conditional probability, and expected value in one interface. It converts between probability and odds formats, and computes the complement automatically. Statistics students, data analysts, and anyone modeling uncertain outcomes use this to reason quantitatively about likelihood and risk.
Frequently Asked Questions
Sobre Esta Calculadora
Probability quantifies how likely an event is to occur on a scale from 0 (impossible) to 1 (certain). Simple events have probabilities based on the ratio of favorable outcomes to total equally-likely outcomes. Compound event rules follow set theory: P(A or B) = P(A) + P(B) − P(A and B) for general events, simplified to P(A) + P(B) for mutually exclusive events. P(A and B) = P(A) × P(B) for independent events.
This calculator handles both discrete and continuous probability scenarios, converting between decimal probabilities, percentages, and odds (the ratio of favorable to unfavorable outcomes used in statistics and gambling). Expected value — the probability-weighted average outcome — is also computed.
Probability is foundational to statistics, machine learning (Bayesian inference), finance (option pricing using the Black-Scholes model), game theory, medical testing (sensitivity and specificity of diagnostic tests), and any decision-making under uncertainty.
Trate os eventos na matemática.
Exemplo Resolvido
Probability that a fair die shows an even number OR a 5
Entradas:
- Event A (even number on a die): P(A) = 3/6 = 0.5
- Event B (rolling a 5): P(B) = 1/6
- Are events mutually exclusive? Yes
Passo a Passo:
- For mutually exclusive events (no overlap): P(A or B) = P(A) + P(B)
- P(A or B) = 3/6 + 1/6 = 4/6 = 2/3 ≈ 0.667
- Probability as percentage: 66.7%
- Complement: P(neither A nor B) = 1 − 2/3 = 1/3 ≈ 0.333
- Odds in favor: (2/3) / (1/3) = 2 : 1