A large group of students took a test inPhysics, and the final grades have a mean of 70 and a standard deviation of 10. If we can approximate the distribution of these grades by a normal distribution, what percent of the students a) Scored higher than 90? b) Should pass the test with an A, B, or C (grades 70)? c) Should make a D or F (grades < 70)?

d) You can find the answers to part a with the normal distribution and by using the Empirical rule. Find the answers to part a and b by the method you did not use already and compare answers.