Find the expected value and the variance of x

Question

Problem

Let a and b be positive integers with a ≤ b, and let X be a random variable that takes as values, with equal probability, the powers of 2 in the interval [2^a, 2 ^b ] . Find the expected value and the variance of X.

The response should include a reference list. Double-space, using Times New Roman 12 pnt font, one-inch margins, and APA style of writing and citations.