You conduct an experiment to determine if mosquitoes are repelled by citronella. In one group, 100 mosquitoes are placed in an enclosure that has had one of its interior sides sprayed with citronella. In other group you place 100 mosquitoes in an enclosure to which no citronella has been applied. At the end of the experiment, you observe that mosquitoes are randomly distributed on all sides of both enclosures. What is the dependent variable in this experiment?