I competed in the Disease Detective event last year at one of our state's regional competitions and I have to say the test wasn't that scary. You need to know simple math equations such as percentages (is/of), averages and the such. There was also an awesome Bonus question where you had to match celebrities with the diseases they had. I would be sure to play some of the games on the official Science Olympiad site because they definitely give you an idea of what work as an epidemiologist is like, which is basically what you are doing on the test. =) Good luck!
♥abigail jolee's 2009 Events: Chem. Lab, Disease Detectives, Egg-O-Naut, Experimental Design and Herpetology.♥