2.The final marks for the Wednesday class in Statistics 101 are ready to be posted. The class average is 72%, with a standard deviation of 9. The distribution of grades is approximately bell-shaped.

a. What percentage of the grades are above 81?

Percentage of grades%

b. What percentage of the grades are below 54? (Round the final answer to 1 decimal place.)

Percentage of grades%

c. What percentage of the grades are between 54 and 90?

Percentage of grades%

d. What percentage of the grades are between 54 and 81? (Round the final answer to 1 decimal place.)

Percentage of grades%

e. What percentage of the grades are between 54 and 99? (Round the final answer to 2 decimal places.)

Percentage of grades%

f. What percentage of the grades are less than 63 or more than 90? (Round the final answer to 1 decimal place.)

Percentage of grades%

3.Health issues are a concern of managers, especially as they evaluate the cost of medical insurance. A recent survey of 150 executives at Elvers Industries, a large insurance and financial firm, reported the number of kilograms by which the executives were overweight. Compute the range and the standard deviation. (Round the final answers to 2 decimal places.)

Number of Kilograms Frequency

0 to under 6 14

6 to under 12 42

12 to under 18 58

18 to under 24 28

24 to under 30 8

Range

Standard deviation