Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 72352

A random variable or stochastic variable is a value that is subject to chance variation (i.e., randomness in a mathematical sense).

1 vote
1 answer
123 views

If $X=Y+Z$ with known pdf of $X$, are $Y$ and $Z$ unique?

Say there are random variables such that $X=Y+Z$ with $Y$, $Z$ independent; knowing the pdfs of $Y$ and $Z$, one can (technically) find the pdf of $X$. Taking it from the other side: if one knows the …
corey979's user avatar
  • 1,264
4 votes

PDF of dependent variables

I specify my approach: Let $X=A+D+\sqrt{(A-D)^2+U}$ with $Y=A+D$ and $Z=(A-D)^2$; hence $A=\frac{Y+\sqrt{Z}}{2}$, $D=\frac{Y-\sqrt{Z}}{2}$ and $U=(X-Y)^2-Z$, with a Jacobian $|J|=\left|\frac{y-x}{2\s …
corey979's user avatar
  • 1,264
4 votes
1 answer
770 views

PDF of dependent variables

In my recent question an answer was given, and I am able to compute it myself. Still, I'd like to understand where does that answer come from. Hence, what's the approach to handle dependent variables …
corey979's user avatar
  • 1,264
17 votes
2 answers
686 views

What's the distribution of $(a-d)^2+4bc$, where $a,b,c,d$ are uniform distributions?

I have four independent uniformly distributed variables $a,b,c,d$, each in $[0,1]$. I want to calculate the distribution of $(a-d)^2+4bc$. I computed the distribution of $u_2=4bc$ to be $$f_2(u_2)=-\ …
corey979's user avatar
  • 1,264
8 votes
2 answers
794 views

PDF of a sum of dependent variables

This is a direct continuation of my recent question. The thing that I actually want to get is the distribution of $a+d+\sqrt{(a-d)^2+4bc}$, where $a,b,c,d$ are uniform in $[0,1]$. Now, the distributio …
corey979's user avatar
  • 1,264
3 votes

PDF of a sum of dependent variables

Just after reading wolfies answer I understood I could calculate the final distribution from the very beginning without all the mid-point steps: M[x_] := M[x] = Evaluate@FullSimplify@ Integrat …
corey979's user avatar
  • 1,264