Math 2.0

Probability theory and stochastic processes Definition

Identically distributed random variables

Builds on Law of a random variable

Definition

Let (E,ℰ)(E, \mathcal{E}) be a set with a σ-algebra. Let XX be a random variable on a probability space (Ω,ℱ,P)(\Omega, \mathcal{F}, P) with values in EE. Let YY be a random variable on a probability space (Ω′,ℱ′,P′)(\Omega', \mathcal{F}', P') with values in EE. XX and YY are identically distributed if they have the same law: P(X∈B)=P′(Y∈B)P(X \in B) = P'(Y \in B) for each B∈ℰB \in \mathcal{E}. One writes X=dYX \overset{d}{=} Y.

Remarks

For real random variables, this holds if and only if XX and YY have the same cumulative distribution function. Identically distributed random variables need not be equal. For a fair coin, the indicator XX of heads and the indicator 1−X1 - X of tails are identically distributed, but they are never equal. If X=dYX \overset{d}{=} Y and gg is a measurable function, then g(X)=dg(Y)g(X) \overset{d}{=} g(Y).

Reading path

To understand this page from the ground up, read these 41 pages in order. The foundations come first.

  1. Construction of the reals from Cauchy sequences concept
  2. Element definition
  3. Integers object
  4. Ordered field definition
  5. Proposition concept
  6. Random experiment concept
  7. Rational numbers object
  8. Real numbers object
  9. Set definition
  10. Ring of integers statement
  11. Disjunction definition
  12. Implication definition
  13. Predicate definition
  14. Ordered pair definition
  15. Union definition
  16. Sample space definition
  17. The rationals form a field statement
  18. Existential quantifier definition
  19. Universal quantifier definition
  20. Cartesian product definition
  21. Subset definition
  22. The rationals form an ordered field statement
  23. Uniqueness quantifier definition
  24. Binary relation definition
  25. Universal set definition
  26. Order on the reals definition
  27. Power set definition
  28. Complement definition
  29. Function definition
  30. Interval definition
  31. Preimage of a set definition
  32. Sigma-algebra definition
  33. Event definition
  34. Borel sigma-algebra definition
  35. Probability axioms concept
  36. Probability measure definition
  37. Probability distribution definition
  38. Probability space definition
  39. Random variable definition
  40. Law of a random variable definition
  41. Identically distributed random variables definition

Where this leads

132 pages build on this one.

Further reading

  1. Web https://en.wikipedia.org/wiki/Independent_and_identically_distributed_random_variables, Definition for two random variables
About this page
Tag01X8YSDTBW
URIm2://01X8YSDTBW
Kinddefinition
WritingW0 stub
MSC60E05
DefinesIdentically distributed random variables
UsesLaw of a random variable

Markdown · JSON · Edit on GitHub

What this page needs for W1

  • an inventory row: the row of the inventory that the node accounts for (0 of 1)

The writing levels say how complete the text of a page is. They do not measure its truth.

What links here

Used by