Question: Whats an independent variable?
Answer: An independent variable is exactly what it sounds like. It is a variable that stands alone and isnt changed by the other variables you are trying to measure. For example, someones age might be an independent variable. Other factors such as what they eat, how much they go to school, how much television they watch arent going to change a persons age. In fact, when you are looking for some kind of relationship between variables you are trying to see if the independent variable causes some kind of change in the other variables, or dependent variables.
Question: Whats a dependent variable?
Answer: Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it. Usually when you are looking for a relationship between two things you are trying to find out what makes the dependent variable change the way it does.
Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in the way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:
Independent variable causes a change in Dependent Variable and it isnt possible that Dependent Variable could cause a change in Independent Variable.
Time Spent Studying causes a change in Test Score and it isnt possible that Test Score could cause a change in Time Spent Studying.
via What are Independent and Dependent Variables?-NCES Kids Zone.