Question 262597: ok so there are 10 questions on a test which is a true or false test. what is the probability that a student can score at least a 70% on the test by just randomly guessing all answers. what if it was a multiple choice test with four choices per question, how does that probability channge
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! ok so there are 10 questions on a test which is a true or false test. what is the probability that a student can score at least a 70% on the test by just randomly guessing all answers.
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>=70% means 7 to 10 correct answers
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The problem is binomial with p=1/2, n = 10, and 7<= x <=10
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P(7 <= x <= 10) = 1-binomcdf(10,0.5,6) = 0.1719
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what if it was a multiple choice test with four choices per question, how does that probability channge.
p = 1/4
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P(7 <= x <=10) = 1-binomcdf(10,0.25,6) = 0.0035...
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Cheers,
Stan H.
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