A student answers a multiple choice examination with questions that have four possible answers each. Suppose...
A student answers a multiple choice examination with questions
that have four possible answers each. Suppose that the probability
that the student knows the answer to a question is 0.80 and the
probability that the student guesses is 0.20. If the student
guesses, the probability of guessing the correct answer is 0.25.
The questions are independent, that is, knowing the answer on one
question is not influenced by the other question.
(a) If there is one question on the exam and he answered the
question correctly, what is the probability he knew the
answer?
(b) If there is two questions on the exam and he answered both
questions correctly, what is the probability he knew both
answers?
(c) How would you generalize the above to n questions, that is, if
the student answered an infinite number of questions correctly,
what is the probability he knew the answers?
Homework Answers
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