Question

You are taking a 100 question multiple-choice exam with 5 choices for answers on each question. Each question is worth 1 point and you are docked 1/5 point for each wrong answer. Suppose you guess on all 100 questions, what is the expected value for your grade?

Answer 1

Answer:

4

Step-by-step explanation:

E(X) = np = 100 × ⅕ = 20

20 correct, 80 incorrect.

80×⅕ = 16

20 - 16 = 4