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Statistics vocabulary · Probability

Random variable

Meaning in statistics, with examples

nounCommon term

In statistics, random variable means: A variable whose value is determined by the outcome of a random process, such as the number of heads in ten coin tosses or the waiting time for a bus.

In Turkish: rastgele değişken, rassal değişken, tesadüfi değişken

How it is used

A core idea in probability courses, usually written with a capital letter (X), while its observed values use lower case (x). A random variable is discrete or continuous and has a probability distribution, an expected value and a variance.

Example sentences

  1. Let X be a random variable representing the number of customers arriving per hour.

  2. A discrete random variable can only take separate values such as 0, 1, 2 and so on.

Common collocations

  • discrete random variable
  • continuous random variable
  • let X be a random variable
  • independent random variables
  • probabilityA number between 0 and 1 that expresses how likely an event is: 0 means it cannot happen and 1 means it is certain.
  • expected valueThe long-run average result of a random variable if the same process were repeated many times, found by weighting each possible value by its probability.
  • distributionThe pattern showing which values a variable takes and how often each one occurs, often pictured as a histogram or a curve.
  • binomial distributionThe probability distribution of the number of successes in a fixed number of independent trials, each with the same probability of success, such as heads in 20 coin tosses.
  • varianceThe average of the squared distances between each value and the mean; it measures spread, and its square root is the standard deviation.

More terms: Probability

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