1. A sample of a professor's class received the following grades for their first test. Calculate the followings for this class (11 points)
2. Sample mean deviation
3. Sample standard Deviation
4. Coefficient of variation

grades	Number of students
40-50	2
50-60	4
70-80	7
90-100	5

If we assume that the grades are only 50, 60, 80, 90, 100,

What would be the following for these grades?

1. Arithmetic mean,
2. Geometric mean
3. Median
4. Standard deviation
5. Coefficient of variation