1. Experimental Design Showing Cause & Effect Relationships

2. Experiments Direct way to test a hypothesis about a cause-effect relationship between factors Hypothesis: Educated Guess

3. Experimental Group The subjects in an experiment who are exposed to the treatment (independent variable) Also called the experimental condition The group being studied and compared to the control group

4. Control Group Are not exposed to the independent variable Results are compared to those of the experimental group Also called the control condition

5. Independent Variable The experimental variable which causes something to happen The “cause variable” The variable manipulated by the experimenter The variable which should change the dependent variable

6. Dependent Variable The experimental variable which is affected by the independent variable The “effect variable” The outcome of the experiment The variable being measured

7. Mrs. Cavell’s Example: Hypothesis: If I give teens $100 each day they then will increase their productivity in class. IV: $100 DV: Productivity EG: Students who get $100 CG: Students who get nothing

8. Which of the following is the Independent Variable in the statement: Justin Time wants to know if wearing a watch actually improves punctuality. 1.Justin Time 2.Punctuality 3.Wearing a Watch 4.None of the above.

9. Dr. Mike Rophone was interested in the relationship between using a sound amplification device and student learning. Which of the following is the dependent variable? 1.Dr. Mike Rophone 2.Relationship 3.Student Learning 4.Sound Amplification Device

10. Example 1 Stew Pidriver wants to know if texting while driving then causes an increase in accidents. IV: DV: EG: CG:

11. Example 2 Holly Day wants to study the relationship between Christmas and credit card spending. IV: DV: EG: CG:

12. Knowing the Difference Use an If/Then Statement If this (independent variable) THEN this happens (dependent variable). If my subject drinks an energy drink (Ind. Variable) THEN they should get a surge in energy (Dep. Variable)

13. Experimental Design Random sample—every member of the population being studied should have an equal chance of being selected for the study Randomization helps avoid false results & bias Double-Blind: Neither the researcher nor the participant knows if they are receiving the placebo