Question

Let X be a discrete random variable. The probability distribution of X is given below:

X	30	10	– 10
P(X)	`1/5`	`3/10`	`1/2`

Then E(X) is equal to ______.

Options

• 6

• 4

• 3

• – 5

Answer 1

Let X be a discrete random variable. The probability distribution of X is given below:

X	30	10	– 10
P(X)	`1/5`	`3/10`	`1/2`

Then E(X) is equal to 4.

Explanation:

E(X) = `30 xx 1/5 + 10 xx 3/10 - 10 xx 1/2` = 4.