A test preparation claims that more than 50% of the students who take their test prep course improve their scores by at least 10 points. Instead of advertising the percentage of customers who improve by at least 10 points, a manager suggests testing whether the mean score improves at all. For each customer they record the difference in score before and after taking the course (After - Before). a) State the null and alternative hypotheses. b) The P-value from the test is 0.65. Does this provide any evidence that their course works? c) From part b, what can you tell, if anything, about the mean difference in the sample scores? a) State the hypotheses. Ho HA b) The P-value is so the test provides evidence that the course works. c) Choose the correct answer below. A. The mean difference for the sample could have been any value within one standard deviation of zero. B. The mean difference for the sample was positive. C. The mean difference for the sample was negative. D. Nothing can be determined about the mean difference for the sample.