Hypergeometric distribution

Gives the probability of drawing exactly x successes when sampling n items without replacement from a finite population of N items containing M successes. It is used for counting-type sampling problems such as drawing defective items from a lot.

P(X = x) = \frac{\binom{M}{x}\binom{N-M}{n-x}}{\binom{N}{n}}

What the symbols mean

discrete random variable counting the number of successes in the sample
number of successes observed in the sample
population size, with N \geq 1
number of success items in the population, with 0 \leq M \leq N-1
sample size drawn without replacement, with 1 \leq n \leq N
binomial coefficient, the number of ways to choose b items from a

About this formula

  • FieldStatistics
  • TopicProbability distributions
  • LevelUniversity
  • Also calledhypergeometric probability mass function, hypergeometric pmf, sampling without replacement probability, probability of x successes without replacement, hypergeometric formula
  • SourceWikidata Q730600

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