Question 477669
In a multiple- choice test, each question has five options. Students will get 3 points for each correct answer. lose 1 point for each incorrect answer, and receive no points for unanswered questions. A student does not know the correct answer for one question. Is it to her advantage or disadvantage to guess an answer? 
1) Show calculations for expected value.
Random Point Values: 3 , -1 , 0
Corresponding Probs: 1/5,4/5, 0
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E(x) = (1/5)*3 + (4/5)*-1 + 0 = (3/5)-(4/5) = -1/5 point per question answered.
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Cheers,
Stan H.
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2) Show all work to solve the problem.
done