16 (a) Which grade is better: A 78 on a test whose mean is 72 and a standard deviation of 6.5, or an 83 on a test whose mean is 77 and standard deviation is 8.4. A 83 B 78 (b) Part B == The grades on a geometry midterm are normally distributed with 70 and a 2.0. Find the z-score for David if he gets a score of 68 on the exam. Type your result in the empty box provided below. Answer: