1.
a. E(X + Y) = 7
b. VAR(X + Y) = 7
c. E(3X − 2Y) = 6
d. VAR(3X − 2Y) = 38
2.
a. E(2S + 5T) = 38
b. VAR(2S + 5T) = 83
c. SD(2S + 5T) = 9.1 (to 2 sig.fig.)
3.
a. E(W) = 1.1 and VAR(W) = 0.49
b. P(W1 + W2 = 4) = 0.09
c. E(W1 + W2) = 2.2 and VAR(W1 + W2) = 0.98
d. P(2W = 4) = 0.3
e. E(2W) = 2.2 and VAR(2W) = 1.96
4.
E(5A − 4B) = 9 and VAR(5A − 4B) = 6.1
5.
a. E(X + Y) = 5
b. VAR(X + Y) = 0.78
c. E(X − Y) = -1.2
d. VAR(X − Y) = 0.78
e. Complete the table for the probability distribution of X +Y
| x + y |
3
|
4
|
5
|
6
|
7
|
| P(X +Y = x + y) |
0.03
|
0.26
|
0.43
|
0.24
|
0.04
|
