Common Probability Distributions

Common Probability Distributions: Notation Reference

Notation Reference for common probability distributions: write, format, verify, and publish clear definitions, assumptions, examples, accessible markup, and portable notation.

Updated 2026-07-26 · Reviewed 2026-07-23 by Chevee Math Tools

Common Probability Distributions: Notation Reference explains parameters, support, moments, modeling assumptions, and notation.

Core notation for Common Probability Distributions

In common probability distributions, the notation usually represents events, random variables, probability measures, parameters, and conditioning information. The table below gives a compact starting set for common probability distributions; define any local variation before the first calculation.

ConceptNotationHow to read it
Event probabilityP(A)probability assigned to event A
Conditional probabilityP(A\mid B)=\frac{P(A\cap B)}{P(B)}probability of A given B when P(B)>0
Expectation\mathbb{E}[X]mean of a random variable under its distribution
Variance\operatorname{Var}(X)=\mathbb{E}[(X-\mathbb{E}X)^2]spread around the expectation

How to read a complete expression

Read P(A) as “probability assigned to event A.” Identify the outer operation first, then its inputs, index set, conditions, and result type. This prevents a superscript, bar, vertical line, or styled letter in common probability distributions from being interpreted by appearance alone.

Conventions that belong in the notation table

  • State whether variables are discrete or continuous.
  • Write the conditioning event or sigma-algebra explicitly.
  • Name the parameterization of every distribution.

Cross-checks before reuse

  • Verify probabilities are nonnegative and normalize to one.
  • Test an extreme or degenerate case.
  • Confirm support and parameter constraints before substitution.

Accessibility and portability

Keep the common probability distributions source selectable and editable. For an isolated character in common probability distributions, Unicode text may be sufficient; for structured expressions, preserve LaTeX, MathML, or a native equation object. When an image of common probability distributions is unavoidable, describe the operation, inputs, conditions, and conclusion rather than listing glyph names.

Verification checklist

  • Verify probabilities are nonnegative and normalize to one.
  • Test an extreme or degenerate case.
  • Confirm support and parameter constraints before substitution.
  • Confirm every symbol used in common probability distributions has one defined meaning in the local context.
  • Reopen the exported file for Common Probability Distributions: Notation Reference and compare it with the editable source.

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How this guide was checked

Page purpose: common distributions notation reference — Look up notation, definitions, and usage conventions

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Verification references

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