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Random Variable

Sure, here’s a definition of a random variable:

Random variable: A function that assigns a numerical value to each outcome of a random experiment.

Formal definition:A random variable is a function from the sample space S of an experiment to the set of real numbers R. A random variable is represented by a letter like X. For every subset A of S, the probability of X falling into A is defined by P(A) = P(X belongs to A).

Key points:

  • Random variable: A function that assigns a numerical value to each outcome of a random experiment.
  • Sample space: The set of all possible outcomes of a random experiment.
  • Real numbers: The set of all numbers.
  • Probability: The probability of a random variable falling into a given subset of its sample space.

Examples:

  • Random variable X: The number of heads obtained in a coin toss experiment.
  • Random variable Y: The number of defective products in a batch of 100 products.
  • Random variable Z: The waiting time for a bus at a bus stop.

Additional notes:

  • Random variables are used to quantify the uncertain outcomes of an experiment.
  • The probability of a random variable falling into a given set can be calculated using the probability mass function (for discrete variables) or the probability density function (for continuous variables).
  • Random variables can be used to perform statistical analyses and make predictions about the outcome of an experiment.

Here are some resources that you may find helpful:

  • Khan Academy: Random Variables: Math/Statistics/Probability/Random Variables
  • Stattrek: Random Variables: Probability/Random Variables
  • Cambridge University: Random Variables: Probability/Random Variables

Please let me know if you have any further questions about random variables.

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