# Math Help - Discrete joint distribution

1. ## Discrete joint distribution

Question 3:

If joing prob dist of X and Y is given by :

F(x,y) = x+y/30, x=0 1 2 3 , y=0 1 2

find P(X>Y)
Does it mean integrate from value 2 to 3 ?

2. Originally Posted by hazel
Question 3:

If joing prob dist of X and Y is given by :

F(x,y) = x+y/30, x=0 1 2 3 , y=0 1 2

find P(X>Y)
Does it mean integrate from value 2 to 3 ?
You only integrate when the random variable is continuous. From what you posted, it's pretty obvious that X and Y are taking on discrete values and are therefore discrete random variables.

Pr(X > Y) = Pr(X = 1 and Y = 0) + Pr(X = 2 and Y = 0) + Pr(X = 2 and Y = 1) + ......

3. ## understood

ok this is clear.

Thanks.