SOLUTION: In a multiple choice test, each question has four options, students get 10 points for each correct answer,lose four points for each incorrect answer, and receive no points for unan

Algebra ->  Probability-and-statistics -> SOLUTION: In a multiple choice test, each question has four options, students get 10 points for each correct answer,lose four points for each incorrect answer, and receive no points for unan      Log On


   

Question 404133: In a multiple choice test, each question has four options, students get 10 points for each correct answer,lose four points for each incorrect answer, and receive no points for unanswered question. the student does not know the answer for one question, is it to her advantage or disadvantage to guess an answer. please show calculation for me
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
In a multiple choice test, each question has four options, students get 10 points for each correct answer, lose four points for each incorrect answer, and receive no points for unanswered question.
the student does not know the answer for one question, is it to her advantage or disadvantage to guess an answer.
----
Determine the expected value:
Random values: 10, -4, 0
Probabilities: (1/4), (3/4), her option
------
E(x) = (1/4)(10)+(3/4)(-4) = (10-12)/4 = -1/2 point
----
It would be better to not answer the question.
======
Cheers,
Stan H.