Suppose your statistics professor reports test grades as z-scores, and you got a score of 2.50 on an exam. a) Write a sentence explaining what that means. b) Your friend got a z-score of -1. If the grades satisfy the Nearly Normal Condition, about what percent of the class scored lower than your friend? a) Choose the correct answer below. A. The score was 2.50 standard deviations higher than the mean score in the class. OB. The score was 2.50 points higher than the mean score in the class. OC. The score was 2.50 points lower than the mean score in the class. OD. The score was 2.50 standard deviations lower than the mean score in the class. b) About % of the class scored lower than your friend. (Type an integer or decimal rounded to one decimal place as needed.)