Good at Stats? earn 50mill credits!

[Divine Intervention]

okay im having a stats exam soon and i absolutly hate stats. ive been getting worse marks in it compared to my other exams all the way from GCSEs to Uni level. anyway can anyone help me with these Covarience questions?

i know how to do E(X), E(Y), the varience questions and Cov(X,Y) but the following have me very confused:



for the first one i need to find Cov(Y,Ysquared) ie Cov(Y,Y^2)

for the second one i need to find Cov(X,Y|x>=14) ie Cov(X,Y given that x is greater or equal to 14).

i have the answers but dont understand how they were obtained. help appreciated and rewarded.

i hate statistics

EDIT: i worked out how to do Cov(Y,Y^2) --> E(Y^3)-E(Y)E(Y^2) --> 28.7 - (8.9*2.7)=2.89. so i only need help with the second one now please

EDIT: can mod change title to 50mill please considering ive done half the work already although worry not mathematicians, im sure to have plenty more questions and will be giving generous rewards for help