Consider these related quantities, a call duration and its cost. Which quantity is the independent variable? Which quantity is the dependent variable?
An independent variable is a variable that is changed or controlled in a scientific experiment. A dependent variable, on the other hand, is a variable that is being measured and tested in a scientific experiment. As the name suggests, the dependent variable is dependent on the independent variable.
In this question, we are looking at the call duration and its cost. The call duration is the independent variable. This is the variable that we can change or alter. The dependent variable is the cost, as this depends on the call duration. The cost of the call will alter as the call duration increases or decreases.