Suppose that you were told that scores on an exam in a large class you are taking ranged from 50 to 100 and that they were approximately bell-shaped.
a. Estimate the mean for the exam scores.
b. Refer to the result about the relationship between the range and standard deviation in Exercise 25. Estimate the standard deviation for the exam scores, using that result and the information in this problem.
c. Suppose your score on the exam was 80. Explain why it is reasonable to assume that your standardized score is about 0.5.
d. Based on the standardized score in part (c), about what proportion of the class scored higher than you did on the exam?