Reference no: EM1316798
Q1) Joint probability distribution of variables X and Y is illustrated in table below, where X is number of tennis racquets and Y is number of golf clubs sold daily in small sports store.
Y
|
1
|
2
|
3
|
1
|
0.30
|
0.18
|
0.12
|
2
|
0.15
|
0.09
|
0.06
|
3
|
0.05
|
0.03
|
0.02
|
a) Compute E(XY)
b) Determine marginal probability distributions of X and Y.
c) Are X and Y independent? Explain.
d) Compute conditional probability P(Y = 2 | X = 1)
e) Compute expected values of X and Y.
f) Compute variances of X and Y.
g) Compute Cov(X,Y). Did you expect this answer? Explain why?
h) Determine the probability distribution of random variable X + Y.
i) Compute E(X + Y) and Var(X + Y) directly using probability distribution of X + Y .
j) Illustrate that Var(X + Y) = Var(X) + Var(Y). Did you expect this result? Describe why?