(Solved):
Two discrete random variables \( X, Y \) follow a distribution with joint function probability mas ...
Two discrete random variables \( X, Y \) follow a distribution with joint function probability mass \[ f(x, y)=P[X=x, Y=y]=\frac{c}{2^{x} \cdot 4^{y}} \] for some suitable real constant \( c \). (a) Find the value of the constant \( c \). (b) Find the marginal probability mass functions of \( X, Y \). (c) Calculate the following probabilities \[ \begin{array}{l} P(X+Y=2) \text { and } \\ P(X+Y>2 \mid Y<2) . \end{array} \]