Consider the following probability mass function for the discrete joint probability distribution for random variables X and Y where the possible values for X are 0, 1, 2, and 3; and the possible values for Y are 0, 1, 2, 3, and 4:
a. What is p(X=x), the pmf of the marginal distribution for X?
b. What is p(Y=y), the pmf of the marginal distribution for Y?
c. If we know in some context that X = 0, what is the probability that Y = 1?
d. If we know in some context that Y = 0, what is the probability that X = 1?
e. State the complete conditional distribution p(X=x | Y=y).
f. State the complete conditional distribution p(X=x | X=x).
g. What are the means of the marginal distributions μx and μy?
h. What are the standard deviations of the marginal distributions σx and σy?
i. What is E(XY), the expected value of X times Y?
j. What is the covariance Cov(X, Y)?
k. What is the correlation coefficient Ïxy? What does this tell us about the relationship between the two random variables?
l. Are X and Y independent random variables? How do you know?