An investigator conducts a study to determine whether there is an association between caffeine intake and Parkinson's disease.He assembles 115 incident cases of Parkinson's disease and samples 1735 healthy from the general population.After interviewing all subjects, he finds that 100 of the cases had high daily intake of caffeine (exposed) prior to diagnosis and 410 of the controls had low daily intake of caffeine (unexposed) prior to the date of the matched case's diagnosis.