Question

1. There are 10 multiple-choice question on exam, each having 5 responses a, b, c, e. Suppose a student guesses the answer to each question, and all the guesses are independent. Hint: Let X be the number of questions answered correctly. Then X ~ Bin(10, 0.20) a) If the student needs to answer at least 9 questions to get A, what is the probability that the student gets A? Hint: P(at least 9 questions answered correctly) = P(X9) =

b) What is expected value of the number of correct answers?

Answer 1