28.  Exam Scores The average score of the students in one calculus class is 110, with a standard deviation of 5; the average score of students in a statistics class is 106, with a standard deviation of 4. Which class is more variable in terms of scores?

29.  Suspension Bridges The lengths (in feet) of the main span of the longest suspension bridges in the United States and the rest of the world are shown below. Which set of data is more variable?

United States:  4205, 4200, 3800, 3500, 3478, 2800, 2800, 2310

World:  6570, 5538, 5328, 4888, 4626, 4544, 4518, 3970

Source: World Almanac.

30.  Exam Scores The average score on an English final examination was 85, with a standard deviation of 5; the average score on a history final exam was 110, with a standard deviation of 8. Which class was more variable?

31.  Ages of Accountants The average age of the accountants at Three Rivers Corp. is 26 years, with a standard deviation of 6 years; the average

salary of the accountants is $31,000, with a standard deviation of $4000. Compare the variations of age and income.