The difference between X axis and Y axis mainly comes from mathematics. Traditionally, the independent variable is put on the X axis and the dependent variable is put on the Y axis, which implies people's cognition of causality, that is, X is the reason for the change of Y. But in economics, price may determine quantity, and quantity may also determine price, and there is no clear causal relationship.

It is consistent with influence and not contradictory to mathematics. The price also changes with the change of demand, which affects the price, so the horizontal axis is Q and the vertical axis is P, and the price is affected by demand.

Extended data:

The dependent variable is y, and this equation is applied to psychological research. The independent variable is the factor or condition that guides the change of the cause variable, so the independent variable is regarded as the cause of the dependent variable. Independent variables can be divided into continuous variables and category variables. If the independent variable manipulated by the experimenter is a continuous variable, the experiment is a functional experiment.

If the independent variable manipulated by the experimenter is a category variable, the experiment is a factor type. In psychological experiments, an obvious problem is to have an organism as the subject (symbol O) to respond to the stimulus (symbol R), that is, S-O-R O-R. Obviously, the stimulus variable here is the independent variable.

Variables that can affect other variables in mathematical equations are called independent variables. If (x) takes any quantity and (y) has only one quantity corresponding to (x), then (x) is called the independent variable of this function accordingly. If (y) is a function of (x), then (x) is the independent variable of this function.

Baidu Encyclopedia-Independent Variable