To compare the two classes, the Coefficient of Variation (COV) can be used.
The formula for COV is this:
C = s / x
where s is the standard deviation and x is the mean
For the first class:
C1 = 10.2 / 75.5
C1 = 0.1351 (13.51%)
For the second class:
C2 = 22.5 / 75.5
C2 = 0.2980 (29.80%)
The COV is a test of homogeneity. Looking at the values, the first class has more students having a grade closer to the average than the second class.
4+6 and 2+8 I’m not sure it is
You would do 120/300 = p/100 and you would get 40%
X=16/3 or 5.33333 based on the fact that the angles are congruent
Are you sure you wrote the question correctly? If I'm doing this right, none of the answers provided are correct.