Let the random variable X represent the number of correct responses on a multiple-choice quiz that has 10 questions. Each question has five multiple-choice answers.

1. What is the probability that the random variable X is greater than or equal to 9 if the person taking the quiz randomly guesses?

2. What is the expected value (or mean value) of X if the person randomly guesses? What is the interpretation of this value?

3. What is the standard deviation of X if the person randomly guesses?