Geometric distribution

Math

Definition

A probability distribution that models the number of trials needed to get the first success in a sequence of independent Bernoulli trials, each with the same probability of success p.

Examples

  • Number of coin flips until you get the first heads
  • Number of free throws until a player makes one (if success rate is 70%)
  • Number of customers a salesperson calls before making the first sale
Key Fact

P(X = k) = (1 − p)^(k−1) · p, where k is the trial number of the first success

Related Terms

Binomial distribution Basic probability Random variables

Study This Concept

Practice geometric distribution with free review games in these units:

AP Statistics Unit 4: Probability Random Variables and Distributions