Probability Formulas & Calculators
Understand probability formulas with explanations, examples and interactive tools.
Probability
Classical Probability
\(P(E)=\frac{\text{favourable outcomes}}{\text{equally likely outcomes}}\)
Valid for equally likely outcomes.
Open calculator →ProbabilityComplement Rule
\(P(A^c)=1-P(A)\)
Probability that A does not occur.
Open calculator →ProbabilityAddition Rule
\(P(A\cup B)=P(A)+P(B)-P(A\cap B)\)
Probability of A or B.
Open calculator →ProbabilityConditional Probability
\(P(A|B)=\frac{P(A\cap B)}{P(B)}\)
When P(B)>0.
Open calculator →ProbabilityBayes Theorem
\(P(A|B)=\frac{P(B|A)P(A)}{P(B)}\)
Bayes theorem requires P(B)>0.
Open calculator →No matching formulas.