Question 908563: Tintin is a student taking a statistics course. Unfortunately, Tintin is not good student. He does not read
the textbook before the class, does not do homework and regularly misses classes. Tintin intends to rely
on luck to pass the next quiz. The quiz consists of 10 multiple-choice questions. Each question has five
possible answers, only one of which is correct. Tintin plans to guess the answer to each question.
a. What is probability that he gets no answer correct?
b. What is probability that he gets two answers correct?
c. What is the probability that he gets all answer correct?
d. What is the probability that he fails the quiz? A mark is considered a failure if it is less than 50%.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The quiz consists of 10 multiple-choice questions. Each question has five
possible answers, only one of which is correct.
P(correct) = 1/5 ; P(wrong) = 4/5
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Tintin plans to guess the answer to each question.
a. What is probability that he gets no answer correct?
Ans: (4/5)^10 = 0.1074
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b. What is probability that he gets two answers correct?
P(x = 2) = 10C2*(1/5)^2*(4/5)8 = binompdf(10,1/5,2) = 0.3020
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c. What is the probability that he gets all answer correct?
Ans: (1/5)^10
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d. What is the probability that he fails the quiz?
A mark is considered a failure if it is less than 50%.
P(0<= x <=4) = binomcdf(10,5^-1,4) = 0.9672
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Cheers,
Stan H.
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