Question

A random variable X can take only two values, 2 and 4 i.e., P(2) = 0.45 and P(4) = 0.97. What is the Expected value of X?

(a) 3.8

(b) 2.9

(c) 4.78

(d) 5.32

The question was posed to me during an internship interview.

I would like to ask this question from Discrete Probability topic in chapter Discrete Probability of Discrete Mathematics

Answer 1

The correct choice is (c) 4.78

For explanation: We know that E(X) = ∑ x*P(x) = 2 × 0.45 + 4 × 0.97 = 4.78, where x={2,4}.