Uniform distribution find E(Y|x)

Click For Summary

Discussion Overview

The discussion revolves around finding the conditional expectation E(Y|x) for random variables X and Y that follow a uniform distribution over the circle defined by x^2 + y^2 ≤ 9. Participants explore the necessary steps and reasoning required to approach this problem, focusing on integration and the limits of the variables involved.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant seeks guidance on how to start solving the problem without requesting a complete solution.
  • Another participant suggests integrating over specific ranges for y, but expresses uncertainty about the correct limits of integration.
  • A third participant clarifies that E(Y|x) involves integrating with respect to y while keeping x fixed, indicating the limits for y based on the circle's equation.
  • A later reply indicates that the participant believes they have arrived at an answer of zero, though they express some uncertainty about its correctness.

Areas of Agreement / Disagreement

There is no consensus on the correct approach or final answer, as participants express varying levels of understanding and uncertainty regarding the integration limits and the resulting expectation.

Contextual Notes

Participants discuss the limits of integration for y based on the circle's equation, but there is ambiguity in the ranges proposed. The discussion does not resolve the mathematical steps necessary to arrive at E(Y|x).

confused88
Messages
22
Reaction score
0
This is the question:

If X and Y have a uniform distribution over the circle x^2 + y^2 [tex]\leq[/tex] 9 find E(Y|x).

Can someone please explain to me, how to answer this question. You guys don't have to give me a solution, but a hint would be nice because I have no idea where to start. Thank you :smile:
 
Physics news on Phys.org
well what i was thinking was that the range is between 3 and 0 and -3 and 0.

Then you integrate x^2 + y^2 with the first range (3 and 0) and then with -3 and 0. Is this right?

Or is the first range y to 3, and then -3 to 0?

I have no idea, please help me
 
"E(y|x)" means the mean value of y for a single value of x. There will only be an integral with respect to y, not x. x is fixed. y ranges between [itex]-\sqrt{9- x^2}[/itex] and [itex]\sqrt{9- x^2}[/itex]. Your final answer for E(y|x) will be a function of x.
 
Thank you for replying. Yupp I think that i got the answer. I got zero at the end, but I'm pretty sure that's right
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
12
Views
3K
  • · Replies 6 ·
Replies
6
Views
5K