Question 79225: A quiz has 8 questions with answer options A and B for each. What is the probability that by pure guess work a student answer at least 6 correctly?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A quiz has 8 questions with answer options A and B for each. What is the probability that by pure guess work a student answer at least 6 correctly?
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It is a binomial problem with n=8, p=1/2, 6<=x<=8
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If you have a Ti calculator use 1- binomcdf(8,1/2,5)= 0.145
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If you do not have a TI you need to figure 8C6(1/2)^6(1/2)2+8C7(1/2)^7(1/2)
+8C8(1/2)8 = 37*(1/2)^8=0.145
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Cheers,
Stan H.
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