Question 293096: if a student randomly guesses at 20 multiple choice questions find the probability that the student gets exactly 5 correct? each question has 4 possible choices.
B. student gets at MOST 5 correct?
C. student gets MORE than 7 correct?
D. Student gets at LEAST 8 correct?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! if a student randomly guesses at 20 multiple choice questions find the probability that the student gets exactly 5 correct? each question has 4 possible choices.
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Binomial Problem with n=20; p = 1/4
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I use a TI calculator to get the following:
B. student gets at MOST 5 correct?
binomcdf(20,1/4,5) = 0.6172
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C. student gets MORE than 7 correct?
1 - binomcdf(20,1/4,7) = 0.8982
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D. Student gets at LEAST 8 correct?
same answer as "C"
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Cheers,
Stan H.
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