phoocat... If double jointed people were say 15% of the population but commited 7 times the amount of homicides per capita of non double jointed people would you maybe look into being double jointed as a contributing cause for their homicide rate?
Obviously... you would look at other factors... were the double jointed people unusually poor for instance. If so.. it would make sense to compare their murder rate with that of non double jointed people that were as poor.
lazs