Q. 9
On a multiple choice examination with three possible answers for each of the five questions, what is the probability that a candidate would get four or more correct answers just by guessing ?
Answer :
In this question, we have the repeated correct answer guessing form the given multiple choice questions are Bernouli trials
Let us now assume, X represents the number of correct answers by guessing in the multiple choice set
Now, probability of getting a correct answer, 
Thus, 
Clearly, we have X is a binomial distribution where n = 5 and 
∴ 
Hence, probability of guessing more than 4 correct answer 
= P (X = 4) + P (X = 5)
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Probability of occurrence of an event | Quiz Time45 mins
Probability of occurrence of an event45 mins
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