{"id":1293,"date":"2016-10-24T03:57:48","date_gmt":"2016-10-24T03:57:48","guid":{"rendered":"http:\/\/101psych.com\/?p=1293"},"modified":"2021-04-21T16:05:44","modified_gmt":"2021-04-21T07:05:44","slug":"controls-in-experiments","status":"publish","type":"post","link":"https:\/\/www.themantic-education.com\/ibpsych\/2016\/10\/24\/controls-in-experiments\/","title":{"rendered":"What is a “controlled variable?”"},"content":{"rendered":"

A controlled variable<\/strong> is a variable that’s kept constant between the conditions of the experiment so that the only difference between the groups is the independent variable.\u00a0<\/strong><\/p>\n

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What extraneous variables would you need to control in an experiment to see if coffee gives you more energy?<\/p><\/div>\n

Imagine you’re doing an experiment on yourself to see if drinking coffee in the morning gives you energy. On Monday you wake up, do yoga and then have a cup of coffee. At the end of the day you rank your energy and give it a 9\/10. On Tuesday you wake up drink orange juice and then at the end of the day you rank your energy 7\/10. This simple experiment seems like it’s saying coffee gives you more energy. But there’s a problem – on both days you didn’t just change the drink, you also did yoga on the coffee day. How do you know it was the coffee that made you feel better and not the yoga? The yoga in this instance is an extraneous variable – it’s a variable other than your\u00a0 independent variable (your morning drink) that could have affected your results.<\/p>\n

You want to make sure you’re just testing the effects of coffee. This means you need to control certain variables, like how much sleep you get, the type of exercise you do during the day, stress levels, etc. Anything you do to keep these extraneous variables the same on both days are\u00a0controlled variables.\u00a0<\/strong><\/p>\n

Learn More:<\/strong><\/p>\n