Answer:
1.2
Step-by-step explanation:
We have given the variance between - group estimate is = 30
And the variance within - group estimate is =25
Now we have to calculate the F ratio
F ratio is defined as the ratio of variance between the group and variance within the group
So F ratio 
So for the given variance F ratio will be 1.2
The answer to this problem would be 2.5.
We know that
if P is the centroid of triangle ABC
so
PD=(1/3)*BD
BD=3*PD-----> BD=3*3-----> BD=9 units
the answer is
BD=9 units