We will be talking about independent and dependent variables during class. I'm using this example to start our conversation: http://biologycorner.com/worksheets/controls.html
If you have a moment please review the page and ask yourself what is a control? What is a variable?
(A control is something that doesn't change during the experiment, a variable is something that does)
Secondly, when graphing our experimental results it is important to graph the dependent variable on the y axis and the independent on the x axis.
The above example doesn't have numbers on the x or y axis... but it does show relationships. Temperature was changed... and the number of species changed. The scientist changed the temperature and watched for the # of species to change. More in class.
Ahead we will look at types of relationship, linear, exponential, and inverse linear relationships. More information can be found: here