Chapter 2.6 (Random Varibles, E(X), Var(X))

Question 1

If X is a random variable and a and b are constants, and Y= a+ bX,

What is Var(Y)?

Answer 1

Var (Y) = b^2 * Var(X)

Question 2

If X is a random variable and a and b are constants, and Y= a+ bX,

What is E(Y)?

Answer 2

E(Y) = a + bE(X)

Question 3

If X_1 and X_2 are random variables, what is Var(X_1 + X_2)?

Answer 3

Var(X_1) + Var(X_2)

Question 4

If X_1 and X_2 are random variables, what is E(X_1 + X_2)?

Answer 4

E(X_1) + E(X_2)