Bobby and Cindy are in different math classes. Bobby got a 75 on his test and Cindy got a 70 (surprisingly low for children of an architect). Bobby’s class had a mean of 80 and a standard deviation of 5. Cindy’s class had a mean of 75 and a standard deviation of 10. Who did better on their test, Bobby or Cindy? I calculated the z score of both and found Bobby's z score higher than Cindy's. Does it means that he has done better than Cindy's??