What is a Probability Distribution

We know that a random variable is an uncertain quantity or a number. Its value is determined by chance. For example, the outcome of rolling a die is random. We could get any number from 1 to 6. In case of a die, the probability of getting any number is 1/6. Each outcome has the same probability. However, the probability of each outcome could be different.

A probability distribution is a graph or a table that describes the probabilities of each outcome of a random variable.

In a probability distribution, each value or outcome of the random variable is represented as x. The probability of getting x is represented as P(x). So, if X is the random variable, we are saying that the probability of random variable X being equal to x is P(X=x) or P(x). This is called the probability function.

The probability distribution of rolling a die is shown below:

xiP(xi)
11/6
21/6
31/6
41/6
51/6
61/6

Note that the sum of all probabilities should be equal to 1 and the probability of each outcome, P(x) is between 0 and 1.

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Data Science in Finance: 9-Book Bundle

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Master R and Python for financial data science with our comprehensive bundle of 9 ebooks.

What's Included:

  • Getting Started with R
  • R Programming for Data Science
  • Data Visualization with R
  • Financial Time Series Analysis with R
  • Quantitative Trading Strategies with R
  • Derivatives with R
  • Credit Risk Modelling With R
  • Python for Data Science
  • Machine Learning in Finance using Python

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