So let's say that I am a drug company and I have come up with a medicine that I think will help folks with diabetes. And in particular, I think it will help reduce their hemoglobin A1C levels. And for those of you who aren't familiar with what hemoglobin A1C is, I encourage you, we have a video on that on Khan Academy, but the general idea is if you have high blood sugar over roughly a three month period of time, high blood sugar, and I could say high average blood sugar, you're going to have a high A1C, a high hemoglobin A1C level. And if you have a low average blood sugar over roughly a three month time, you're going to have a lower hemoglobin A1C. So if taking the pill seems to lower folks' A1C levels more than is likely to happen due to randomly or due to other variables, well then that means that your new pill might be effective at controlling folks' diabetes. So in this situation, when we're constructing an experiment to test this, we would say that whether or not you are taking the pill, this is the explanatory variable, explanatory variable, and the thing that it is affecting, the thing that you're hoping has some response, in this case, the A1C levels are your indicator of whether it has helped controlling the blood sugar, we call that the response variable. That right over there is the response variable.