The control group

# The control group

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## The control group

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1. The control group • What is the control group? • Ex: you are testing whether putting a plant under a bright lamp makes it grow faster. • Independent variable: • Control group: • Dependent variable: The control group is missing the variable you are testing!

2. The control group • You wonder whether putting salt on a cucumber will keep it from rotting? • Independent variable: • Control group: • Dependent variable:

3. The control group • Does eating five KitKats after dinner make your sister fall asleep earlier than usual? • Independent variable: • Control group: • Dependent variable:

4. So what does a control group tell you? • Tells you whether your independent variable actually had an effect! • It somehow affected the group you were testing • Example: Your sister and the KitKats

5. Experiment 1 • Did eating KitKats have an effect on what time your sister fell asleep? • How do you know?

6. Experiment 1 Experiment 2 Experiment 3

7. Control group • If the results of a control group and experimental group are the same, the variable has no effect. • If the results of a control group and experimental group are DIFFERENT, the variable has an effect.