That right over there is the response variable. So how are we actually going to conduct this experiment? Well, let's say that we have a group of folks, let's say that we have been given a group of 100 folks who need to control their diabetes. So 100 people here who need to control their diabetes. And we say, all right, well, let's take half of this group and put them into, I guess you could say, a treatment group and another half and put them into a control group and see if the treatment group, the one that actually gets my pill, is going to improve their A1C levels in a way that seems like it would not be just random chance. So let's do that. So we're going to have a control group.