what caused the dust bowl
Biology Honors 12
Part II. Scientific Method: Controlled Variables
There are many different types of experimental procedures that can present the experimenter with problems that must be solved before reliable data can be collected. One such problem presents itself when many variables affect the dependent variable. For example, you want to determine the best method for studying for a test. You have taken many tests and have an idea that making note cards before a test will help you get a good grade.
You pose a question, “Will using note cards help me get a good grade on tests?” You set up a test in which you use note cards for one test (experimental group) and plan to take the next test without note cards (control group). Your independent and experimental variable will be the note cards, the dependent variable will be the grade you get on the test.
Immediately, you see the problems. What if one test is a math test (hard) and the other is a health test (nobrainer)? What if you have time to study for one test and don‟t have the time to study for the other test? What if you are feeling great the day you take one test and feel lousy the day you take the next test? All of these differences are variables that can affect the dependent variable (your grade). You need a way to control these variables so that you can be sure that any differences between the data in the control group and the experimental group is caused by the experimental variable alone.
Controlled variable -variables that can affect the dependent variable. Controlled variables are „controlled‟ by the experimenter. They are held same between both the control group and the experimental group so that the only variable that is different between the two groups is the experimental variable.
Once you recognize what variables you need to control, you can set up your experiment. You use note cards for two different history tests. You plan to study 2 hours for each test. You eat breakfast before
Part II. Scientific Method: Controlled Variables
There are many different types of experimental procedures that can present the experimenter with problems that must be solved before reliable data can be collected. One such problem presents itself when many variables affect the dependent variable. For example, you want to determine the best method for studying for a test. You have taken many tests and have an idea that making note cards before a test will help you get a good grade.
You pose a question, “Will using note cards help me get a good grade on tests?” You set up a test in which you use note cards for one test (experimental group) and plan to take the next test without note cards (control group). Your independent and experimental variable will be the note cards, the dependent variable will be the grade you get on the test.
Immediately, you see the problems. What if one test is a math test (hard) and the other is a health test (nobrainer)? What if you have time to study for one test and don‟t have the time to study for the other test? What if you are feeling great the day you take one test and feel lousy the day you take the next test? All of these differences are variables that can affect the dependent variable (your grade). You need a way to control these variables so that you can be sure that any differences between the data in the control group and the experimental group is caused by the experimental variable alone.
Controlled variable -variables that can affect the dependent variable. Controlled variables are „controlled‟ by the experimenter. They are held same between both the control group and the experimental group so that the only variable that is different between the two groups is the experimental variable.
Once you recognize what variables you need to control, you can set up your experiment. You use note cards for two different history tests. You plan to study 2 hours for each test. You eat breakfast before