Question 421256: 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? Show your calculations for expected value. Show your work for full credit.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 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.
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Random variable values: 3,-1,0
Corresponding probabilities: 1/5,4/5,0/5
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A student does not know the correct answer for one question. Is it to her advantage or disadvantage to guess an answer? Show your calculations for expected value. Show your work for full credit.
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E(x) = (3 -4 + 0)/5 = -1/5
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Cheers,
Stan H.
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