Answer:
Option C) 2.78
Step-by-step explanation:
We are given the following in the question:
Grade: A B C D F
Value: 4 3 2 1 0
Probability: 0.20 0.50 0.30 0.08 0.02
We have to find the expected value.
Formula:
[tex]E(x) = \displaystyle\sum x_iP(x_i)\\\\E(x) = 4(0.20) + 3(0.50) + 2(0.20) + 1(0.08) + 0(0.02)\\\\E(x) =2.78[/tex]
Thus, the correct answer is
Option C) 2.78