Question 435144
A test consists of 10 true-or-false questions. An answer is randomly chosen for each question.
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Binomial Problem with n = 10 and p = 1/2
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7. (1 point) What is the probability of answering exactly 4 questions correctly? Answer in fraction.
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P(x = 4) = 10C4*(1/2)^4*(1/2)^6 = 210/1024
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8. (1 point) What is the probability of answering at least 2 questions correctly? Answer in fraction.
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P(x>= 2) = 1- P(0<= x <=1)
= 1 - [P(x=0) + P(x=1)]
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= 1- [10C0(1/2)^10 + 10C1(1/2)^10]
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= 1 -[(1+10)/1024]
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= 1013/1024
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Cheers,
Stan H.
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