Question

Each question on a multiple-choice exam has four choices. One of the choices is correct, worth four points. Another choice is wrong but carries partial credit of one point. The other two choices are wrong and worth negative one point. If a student picks answers at random, what is the expected value of his or her score for a problem?.

Answer 1

0.75

Explanation:

To find the expected value, we multiply the point values of each choice by the probability of choosing it and then add them together.

The probability of choosing each question is 1/4 or 0.25 as there are 4 multiple choice options.

Choice 1: 0.25 * 4 = 1

Choice 2: 0.25 * 1 = 0.25

Choice 3: 0.25 * -1 = -0.25

Choice 4: 0.25 * -1 = -0.25

_________________________

Expected Value = 0.75