Sum of squared uniform random variables

Click For Summary
SUMMARY

The discussion focuses on calculating the probability that the sum of the squares of two independent uniformly distributed random variables, X and Y, both ranging from 0 to 1, is less than or equal to one. The key equation used is P(Z<1) = P(X^2 + Y^2 < 1). Participants clarify that to find this probability, one must consider the condition Y ≤ √(1 - X^2), which defines the area under the curve in the unit circle. Understanding the properties of uniform distributions and their transformations is essential for solving this problem.

PREREQUISITES
  • Understanding of uniform distributions, specifically uniform random variables between 0 and 1.
  • Knowledge of probability theory, particularly the concept of cumulative distribution functions.
  • Familiarity with transformations of random variables, including squaring and taking square roots.
  • Basic geometry of the unit circle and its relation to probability calculations.
NEXT STEPS
  • Explore the concept of joint probability distributions for independent random variables.
  • Learn about the geometric interpretation of probabilities in two-dimensional spaces.
  • Study the properties of uniform distributions and their applications in probability theory.
  • Investigate the use of Monte Carlo simulations to approximate probabilities involving random variables.
USEFUL FOR

Students studying probability theory, mathematicians interested in random variable transformations, and anyone seeking to understand the geometric interpretation of probability in two dimensions.

mjkato
Messages
2
Reaction score
0

Homework Statement


If X and Y are independent uniformly distributed random variables between 0 and 1, what is the probability that X^2+Y^2 is less than or equal to one.

Homework Equations


P(Z<1) = P(X^2+Y^2<1)

For z between 0 and 1, P(X^2<z) = P(X < √z) = √z

The Attempt at a Solution


I'm a tad lost- I assume what you'd be looking for is the probability that Y^2 is less than or equal 1-X^2, or rather that Y is less or equal to √(1-X^2). Is that all there is to it?
 
Physics news on Phys.org
mjkato said:

Homework Statement


If X and Y are independent uniformly distributed random variables between 0 and 1, what is the probability that X^2+Y^2 is less than or equal to one.

Homework Equations


P(Z<1) = P(X^2+Y^2<1)

For z between 0 and 1, P(X^2<z) = P(X < √z) = √z

The Attempt at a Solution


I'm a tad lost- I assume what you'd be looking for is the probability that Y^2 is less than or equal 1-X^2, or rather that Y is less or equal to √(1-X^2). Is that all there is to it?

You have to remember something really important about variables between 1 and zero. Here it is:

if xε[0,1[ then x^2<x and √x> x I think that should help you a bit
 

Similar threads

Replies
9
Views
3K
  • · Replies 2 ·
Replies
2
Views
1K
Replies
2
Views
2K
Replies
6
Views
1K
Replies
9
Views
4K
Replies
23
Views
2K
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
7
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K