Dear Armen,

 Please consult

https://sites.math.rutgers.edu/~zeilberg/Hist21/q5S.pdf

for the full solutions.

You got 6 points (out of 10).

#4(i) was wrong. #4(ii) was right if you would have gotten (i) right, but still gave you a point.

 Best wishes,

   Dr. Z.