Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 2008-01-27 07:25:02

MarkusD
Member
Registered: 2006-10-08
Posts: 28

Joint Probability Question

Im having a hard time with joint probability when the probability has something to do with X and Y togther (as in parts b and c). Can anyone help with the following question:


If the joint probability density of X and Y is given by:

f(x,y)= 2 for x>0, y>0, x+y<1
        = 0 elsewhere

find:

a) P(X≤1/2, Y≤1/2)
b) P(X+Y>2/3)
c) P(X>2Y)
d) an expression for the values of the joint distribution function of X and Y when x>0, y>0, x+y<1


The answers are 1/2, 5/9, and 1/3 with part d) not being in the back of the book but I think I can figure that out once I know what Im doing for part b and c.

For part a, I just took the double integral from 0 to 1 for x and y and came up with 1/2 once it was all evaluated. Not sure about the others and my book isnt too helpful here.

Offline

Board footer

Powered by FluxBB