A multiple choice quiz consists of 20 questions, each with 3 possible equally likely answers. If a student guesses at the answer to each question, then the mean number of correct answers selected by the student is?
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To find the mean number of correct answers selected by the student, we need to calculate the expected value of the number of correct answers.
In this case, there are 20 questions and each question has 3 possible answers. Since the student is guessing, the probability of selecting the correct answer for each question is 1/3.
The expected value of the number of correct answers can be found by multiplying the number of questions (20) by the probability of selecting the correct answer (1/3).
Expected value = number of questions * probability of selecting the correct answer
= 20 * (1/3)
= 20/3
Therefore, the mean number of correct answers selected by the student is 20/3.