What to NOT include on my resume

I am updating my resume for the upcoming school year, and I am including my summer internship. However, I am concerned about the level of detail I should go into.

This last summer I worked at a hedge fund and was primarily responsible for accounts payable. However, I did have some other interesting assignments that I feel might be more applicable to IB.

For example, I was put in charge of creating a powerpoint presentation for a director based on his notes. I feel like this might be something that could directly translate into IB, but it also seems like a very small accomplishment to include on a resume. Should I include it?

Also, I was put in charge of forecasting the income statement of a small private company (owned by the PM of the fund). It was a great experience and I learned a lot about financial modeling. However, it was not the most scientific forecast. The company was in the red, and while I based a lot of the forecast on revenue, I also relied heavily on management's future operating assumptions. I am going into my junior year in school, and I hope to land an IB position this summer. I just don't want to be in an interview and be called out for my unscientific forecast. Would I be better off including this experience or not?

Thanks for the help.