Question
Question: A random variable x has E(x) = 2, E(x<sup>2</sup>) = 8, V(x) = .........
A random variable x has E(x) = 2, E(x2) = 8, V(x) = ......
A
3
B
4
C
5
D
6
Answer
4
Explanation
Solution
V(x) = ∑ (x-2)2 P(x) = ∑ x2 P(x) – 4
= E(x2) - 4 = 8-4 = 4