A multiple-choice quiz contains ten questions. For each questions there are one correct answer and four incorrect answers. A student gets three correct answers on the quiz. Test the hypothesis that the student is guessing.
10 questions, 3 (questions correct answered) correct answers
5 choices per question;
probability for guessing the right answer is therefor
probability for guessing the wrong answer is therefor
=> probability("three right answers") =
the probability of guessing exactly 3 correct answers out of 10 is 20% (=0.2)