# Joint probability mass function

1. Mar 10, 2015

### zyQuzA0e5esy2y

2 coins
Ω = {HH, HT, TH, TT}
0 = Tails
PX,Y(x,y) = P({TT} n {HH}) for (x,y) = (0,0)
P({HH, HT,TH} n {HH}) for (x,y) = (1,0)
P({TT} n {TT, TH, HT}) for (x,y) = (0,1)
P({HH,HT,TH} n {TH,HT,TT}) for (x,y) = (1,1)
0 otherwise

PX,Y(x,y) = P(0) for (x,y) = (0,0)
P({HH}) for (x,y) = (1,0)
P({TT}) for (x,y) = (0,1)
0 otherwise
PX,Y(x,y) = 0.25 for (x,y) = (1,0)(0,1)
0.50 for(x,y) = (1,1)
0 otherwise

That's basically the lay out i was given.
im not sure how to read for(x,y) = (0,0) and the others similar to it.

Solved it thank you, if anyone is curious i forgot to mention that X = 0 if the outcome equals to TT and if X = 1 for the outcome if it equals to HH HT TT..
Y = 0 if the outcome is equal to HH
Y = 1 if the outcome is equal to HT TT TH

Last edited: Mar 10, 2015
2. Mar 15, 2015

### Stephen Tashi

If your question is about how to read notation, the way you have presented the notation isn't coherent. For example, I think you are using "n" to mean the intersection symbol $\cap$.

If this notation comes from a problem, I suggest you post the problem in the homework section and quote the entire problem exactly.

Perhaps you can use LaTex: https://www.physicsforums.com/help/latexhelp/