Probability Rules

Mutual Exclusivity

A and B are independent events. A and B cannot occur simultaneously. A and B are not related. Opposite for non-mutual exclusivity: (A and/or B)

Binomial Distribution

• Multiplication Rule = P (A and B) = P (A) P (B)

• Conditional Probability = P (A/B) = P (B) • P (A/B)

(not mutually exclusive) = P (A) + P (B) - P (A) P (B)

Outcomes are limited to two choices Decision tree analysis: Dead or alive, sick or well, treat medically or treat surgically, radiotherapy or chemotherapy Decision tree cost-effectiveness analysis Marginal cost-effectiveness analysis Threshold (break-even) analysis

Probability rules

Probability of

Probability of

Probability of A & B Probability of (A or B) = P(A) + P(B) - P(A and B) Probability of (a and B) = P(A) X P(B) (if independent) Probability of (A and B) = 0 (if mutually exclusive

Probability of A & B

Probability of B

Probability of (A or B) = P(A) + P(B) - P(A and B) Probability of (a and B) = P(A) X P(B) (if independent) Probability of (A and B) = 0 (if mutually exclusive

Probability of (A or B) = P(A) + P(B) (if mutually exclusive) 