How does the independent variable affect the dependent variable?

Im doing a science fair project, but i dont understand what this means.How does the independent variable affect the dependent variable?
It's simple really. The dependent variable 'depends' on the value the independent variable takes for its value.



Say you have: y = 3x - 2



This is the equation for a straight line right? Well, 'y' is the dep. variable, and 'x' is the indep. variable. So 'x' takes on any value you wish to give it. So if I assign a value of one (1) to x then y HAS to be 3*1 - 2 = 1.



So y = 1 ONLY when x has been given its value.



Understand?





Think of it like this:



When you go to a restaurant, you can ONLY get what the restaurant offers on its menu. You can't go to a hot dog joint and say "Hey....gimme a fillet mignon!".......right? Your meal DEPENDS on the menu.....your meal is 'dependent' upon the offerings of that restaurant...and the offerings of the restaurant are like the independent variable.



Does that help????How does the independent variable affect the dependent variable?
y depends onx