It's more of a science-in-general thing: The near-universal [1] convention used in drawing graphs is to put the independent variable on the x axis. If the in

It's more of a science-in-general thing: The near-universal [1] convention used in drawing graphs is to put the independent variable on the x axis. If the independent variable is price, then your thought process will be: "If the price is $100, then there will be 1000 buyers. If the price is $150, then there will be 700 customers." It's easy to think about things that way. If the independent variable is demand, then your thought process will be: "If there are 1000 people buying the product, it must cost $100. If there are 700 buyers, then it must cost $150." It seems counterintuitive to think in this way. [1] Except in economics, of course!