2.5. Model selection. Each of the models presented above can be summarized by the set of parameters that may vary freelyother parameters being fixed. Let us consider a model H. For each value h of the free parameters in the freely variable parameter space H (h is a vector of the values of all the free parameters), we can calculate for each population k the probability of generating the number of infected males and females actually observed. We call it L k (h|D k ), where D k represents the data restricted to population k; D k is defined by the number of infected males and females in population k.