What is the geometric distribution and where is it used?

Updated May 17, 2026

Short answer

The geometric distribution models the number of trials needed to get the first success in repeated Bernoulli trials.

Deep explanation

The geometric distribution assumes independent Bernoulli trials with constant success probability p. It answers the question: how many attempts until the first success occurs. It has the memoryless property, meaning future probabilities do not depend on past failures.

Real-world example

Number of calls a sales agent makes before closing a deal.

Common mistakes

  • Confusing geometric distribution with binomial distribution.

Follow-up questions

  • What is memoryless property?
  • What is expected value of geometric distribution?

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