Respuesta :
Answer:A)0.75
Step-by-step explanation:
Given
There are four options to a question
out of which one is correct with 4 points
one is wrong but carries 1 point
Other two are wrong with a negative Point
Probability of selecting an option is [tex]\frac{1}{4}[/tex]
Expected score[tex]=\frac{1}{4}\times 4+\frac{1}{4}\times 1+\frac{1}{4}\times (-1)+\frac{1}{4}\times (-1)[/tex]
Expected score=1+0.25-0.5
Expected score=0.75
A student picks answers randomly then the expected value of his or her score for a problem is 0.75. The correct option is A.
What is the expected value?
Expected value means possibility. It deals with the occurrence of a random event. Its basic meaning is something is likely to happen.
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 for one point.
The other two choices are wrong and worth a negative one point.
Each has a probability of getting selected is 0.25.
Then the expected value will be.
[tex]\rm Expected \ value = 0.25 * 4 + 0.25 *1 + 0.25*(-1) + 0.25 * (-1)\\\\Expected \ value = 1 + 0.25 - 0.25 - 0.25\\\\Expected \ value = 1.25 - 0.5 \\\\Expected \ value = 0.75[/tex]
Thus, the expected value of his or her score for a problem is 0.75.
More about the Expected value link is given below.
https://brainly.com/question/3913865
