Since you are looking at the proposition that a good balanced breakfast helps concentration then the independent variable is a good balanced breakfast.
However, if your study was simply looking at the relationship between a good balanced breakfast and concentration in school, either variable could be the independent variable. It could be argued that only by concentrating in school would you learn what a good balanced breakfast was.
Breakfast
Breakfast
It depends on which variable is independent, and which one is dependent (its value is determined by a function of the independent variable). So suppose that concentration is a function of an arbitrary length (the length is what determines concentration). The independent variable (length) is put on the horizontal axis, and the dependent variable (concentration) is put on the vertical axis.
Concentration of sugar in the water
The dependent variable of pH is its acidity. The independent variable is whatever substance is being tested for pH levels.
Dependant variable: the variable you measure in an experiment. It changes due to external factors affecting it. It can be time taken, or distance traveled... ect. Independant variable: the variable you change in an experiment. It can be the amount of time, or concentration of a substance... ect. Generally continuous variables, though not always.
The independent variable in a titration is the volume of titrant added to the analyte solution. It is controlled by the person conducting the experiment and is typically plotted on the x-axis of a titration curve.
The independent variable.
Changes in the independent variable are independent of changes in any other variable,
The independent variable.
the dependent variable changes with the independent variable. the independent variable only changes when changed by the experimenter. Time is usually an independent variable.
The Independent variable is the one you control. The dependent variable is controlled by the Independent Variable.