# Joint probability problem

• Oct 13th 2010, 06:03 AM
K A D C Dilshan
Joint probability problem
I am almost lost with this problem since I have a very basic idea about joint probabilities.

Qn
Random variables X and Y are uniformly distributed in the triangular region $\displaystyle 0<=y<=x<=1$. Find fxy(x,y), the joint probability density function of X and Y.

my question is am I allowed to take conditional probabilities of X and Y are also uniformly distributed ?

descriptive answer will be highly appreciated.
• Oct 17th 2010, 12:56 PM
scherz0
Hello there,

Perhaps you could state what $\displaystyle f_{X,Y} (x, y)$ you were given? A $\displaystyle f_{X,Y} (x, y)$ does not have to be a conditional probability function.

In any case, the joint probability density function, $\displaystyle f_{X,Y} (x, y)$, has this relation with the cumulative density function: $\displaystyle f_{X,Y} (x, y) = \frac{\partial}{\partial x} \frac{\partial}{\partial y} F_{X, Y} (x, y)$.

I hope that this helps!