What is a Response Variable?
A Response Variable (or dependent variable) is that variable whose variation depends on other variables. The response variable is often related to the independent variable, sometimes denoted as the explanatory variable. In short, the response variable is the subject of change within an experiment, often as a result of differences in the explanatory variables.
How does a Response Variable work?
To better understand a response variable, it is helpful to incorporate an example. Image you're a scientist who wants to understand the effects of cancer treatment plans for cancer patients. If you are comparing two treatment approaches, chemo or surgery, the response variable is efficacy in the form of survival time. The two different approaches define the explanatory variables, as they may or may not affect the response variable. Often, real-world examples will include far more explanatory variables, such as a patient's age, weight, and health.
Different explanatory variables are used to best try and explain or predict the response variable. For example, in reference to our situation above, a patient's age may provide insight about a patient's survival time, however another explanatory variable, such as treatment plan, may provide a more accurate explanation for the accumulated data.