Key Concepts
- A hypergeometric distribution does not consist of Bernoulli trials.
- In a hypergeometric experiment, the probability of “success” is not the same, because sampling is done without replacement, which means each selection is not independent.
- The number of trials in a hypergeometric experiment is fixed.
Glossary
hypergeometric experiment: a statistical experiment with the following properties:
- You take samples from two groups.
- You are concerned with a group of interest, called the first group.
- You sample without replacement from the combined groups.
- Each pick is not independent, since sampling is without replacement.
- You are not dealing with Bernoulli Trials.
hypergeometric probability: a discrete random variable [latex](RV)[/latex] that is characterized by:
- A fixed number of trials.
- The probability of success is not the same from trial to trial.
We sample from two groups of items when we are interested in only one group. [latex]X[/latex] is defined as the number of successes out of the total number of items chosen. Notation: [latex]X \sim H(r, b, n)[/latex], where [latex]r =[/latex] the number of items in the group of interest, [latex]b =[/latex] the number of items in the group not of interest, and [latex]n =[/latex] the number of items chosen.