Handout 11.1:

DESIGNING A FACTORIAL EXPERIMENT

1. What is your dependent measure?

2. What is your first independent variable?
   

   Is this variable a true independent variable?
   Why or why not?

   Can you make statements about the effects of this variable?
   Why or why not?

3. What is your second independent variable?

   Is this variable a true independent variable?
   Why or why not?

   Can you make statements about the effects of this variable?
   Why or why not?

4. Graph your predicted results.

   
   

5. What is your hypothesis about the effect of your first independent variable?
   • Explain how this hypothesis is consistent with your graph. That is, how could someone tell, by looking at your graph, what you are predicting.

   • Why do you think this hypothesis will be supported?

   • Why do you think this hypothesis is worth testing?

6. What is your hypothesis about the effect of your second independent variable?
   • Explain how this hypothesis consistent with your graph.

   • Why do you think this hypothesis will be supported?

   • Why do you think this hypothesis is worth testing?

7. What is your hypothesis about the interaction effect?
   • Explain how your interaction prediction is consistent with the definition of an interaction. Remember that your hypothesis should fit the formula:
     The effect of varying independent variable (B) _______
     on the dependent variable __________
     will be different (stronger, weaker, opposite) for the
     (A1) _____ groups than for the (A2) ______ groups.

   • Explain how this hypothesis is consistent with your graph.

   • Why do you think this hypothesis will be supported?

   • Why do you think this hypothesis is worth testing?

8. How will you assign subjects to condition? Why?

9. How many participants would you use? Why?

10. Fill in the following ANOVA table for your proposed study:

    Source of Variance	Degrees of Freedom
    A X B Interaction
    Error
    Total

11. You have already graphed your predicted results. Now, graph two other possible outcomes of your study.

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    Handout 11.2

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