Salary Rage	Number of Employees
PHP 51-100	15
PHP 101-150	18
PHP 151-200	78
PHP 201-250	56
PHP 251-300	18
PHP 301-350	64
PHP 351-400	70
PHP 401-450	18
PHP 451-500	12

Solve for

1. Mean
2. Median
3. Mode
4. Range
5. D7
6. P85
7. Inter-quartile range
8. Variance
9. Standard deviation
10. Cumulative frequency above D4
11. How many employees have salary above 250?
12. How many employees have salary below 351?
13. Number of employees with salary between 100 to401
14. Total sample
15. Class size