I'm making a graph, but I can't tell which is the independent or dependent variable?

they are "dollars spent" and "gallons bought". which one depends on the other?

the "gallons bought" is the dependent variable. the "dollars spent" is the independent variable.

It really could be either, if you had five dollars, and spend it on gasoline, the money would be the indep variable, and gallons the dependent. But the usual case is we are filling a tank, so gallons is the indep variable, and money the dependent.

thanks

To determine which variable is the independent variable and which one is the dependent variable, you need to consider the cause-and-effect relationship between them. In this case, think about what directly affects the other.

In the given scenario, the "dollars spent" is likely the independent variable because it is within the control of the person making the purchase decision. The "gallons bought" would then be the dependent variable because it is influenced by the amount of money spent.

To confirm this, you can perform a simple logic test: Would the quantity of "gallons bought" change if the "dollars spent" were to change? In this case, it is more logical to assume that changing the amount of money spent would directly influence the quantity of gasoline purchased, rather than the other way around.

Thus, "dollars spent" is the independent variable, and "gallons bought" is the dependent variable in this scenario.