A multiple choice test has ten questions each with four possible answers of which only one is the correct answer . what is the probability that sheer guess work yields 5 to 10 correct answers ?
This can be solved by using the binomial distribution, where the probability of guessing the correct answer to a question is 0.25. P(5 correct) = 0.0584 P(6 correct) = 0.0162 P(7 correct) = 0.0031 P(8 correct) = 0.0004 P(9 correct) = 0.0000 P(10 correct) = 0.0000 P(5 to 10 correct) = 0.0781 or 7.81%
