What is the mean of this discrete random variable? (That is, what is E(X), the expected value of X?) A. 20
B. 18.59
C. 19
D. 19.625

Multiply each X by the corresponding probability P(X), then take the sum.

B

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

note: the best i know.

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8