(adsbygoogle = window.adsbygoogle || []).push({}); Stats/Probability Theory REALLY need help :(

I really need some help.

I have a joint probability mass function...

P(X=x, Y=y) = (20Cx,y,20-x-y)(0.1)^x(0.3)^y(0.5)^(20-x-y)

where 0</= x + y </= 20

b) show that the margninal distribution of X is binomial

c) find E[XY]

Somebody please help me.

Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Stats/Probability Theory REALLY need help

**Physics Forums | Science Articles, Homework Help, Discussion**