Ellie and Yan began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Ellie took a test in English and earned a 71.9, and Yan took a test in Art History and earned a 64. Use the fact that all the students' test grades in the English class had a mean of 72 and a standard deviation of 9.8, and all the students' test grades in Art History had a mean of 66.4 and a standard deviation of 10.6 to answer the following questions. Round all z-scores to 2 decimals. a) Calculate the z-score for Ellie's test grade. b) Calculate the z-score for Yan's test grade