Key Club District Convention:I need to wear Formal Business wear and Casual Business wear whats the difference?

I need to go to the PA District Key Club Convention at Hershey Park on March 2-4th so its coming up. On the list of what I need it says casual clothing (jeans and stuff) but then it says Business Formal and Business Casual but in the parenthesis it says the same thing for both... so what do I wear for each? Could you give me examples and possibly links to pictures or websites please. Thank you so much. And do realize that I am a 16 year old girl so the clothing needs to be appropriate for my age. THANKS!