X Number Of Months 1 2 3 4

Y Total Charges 170 230 290 350

What is the independent quantity? What is the dependent quantity?
I know that independent means the one that changes. Would the total charges be independent

No.

An independent variable is the potential stimulus or cause, usually directly manipulated by the experimenter, so it could also be called a manipulative variable.

A dependent variable is the response or measure of results.