In an experiment, there is one variable whose value you must wait to see, and (at least) one that you purposely set.\u00a0 The variable you set is called the independent variable<\/strong>.\u00a0 The variable you’re curious about is the dependent variable<\/strong>.<\/p>\n A control<\/strong> group – or\u00a0simply “control” – is one that you leave alone.\u00a0 You impose changes on the test<\/strong> group by changing the value of the independent variable.\u00a0\u00a0Then, you\u00a0give the changes\u00a0time to affect the test group.\u00a0\u00a0Finally, you measure the test group’s dependent variable in order to discover the effect of the changes you imposed.<\/p>\n The typical example to illustrate the roles of these variables is a plant-growing experiment.\u00a0 If you want to know if using fertilizer accelerates plant growth, your control group will be plants that don’t get fertilizer.\u00a0 The test group will be plants that do get fertilizer.\u00a0 The independent variable will be how much fertilizer you give to each plant.\u00a0 Finally, the dependent variable will be how much each plant grows over the course of the experiment.<\/p>\n There are other terms that relate to the scientific method, but those are generally better documented.\u00a0 However, we might look at them here in a future post.<\/p>\n