Questions on Regressions and F/T Tests


So I am basically doing this Statistics assignment for extra credit and I am totally confused.

I feel ok with my answers for the first two questions but it would be nice to know if they are actually correct, or what I did wrong. I am totally lost when it comes to 3 and 4. I feel strongly that my 3 is actually incorrect, and am lost on 4. I will provide links to all of them.!112&authkey=!AJvZL6P5dTtm4xo&ithint=file,xlsx!114&authkey=!AJKV-MTkxiCJnzk&ithint=file,xlsx!111&authkey=!AA23uf8-dAzBvDg&ithint=file,xlsx!113&authkey=!AP1hgO5YjoyFfhM&ithint=file,xlsx

If you could tell me what I have done wrong or what I need to do instead, I would be very grateful.