complex experimental designs © 2012 the mcgraw-hill companies, inc
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COMPLEX EXPERIMENTAL DESIGNS
© 2012 The McGraw-Hill Companies, Inc.
Define a factorial design and why a researcher would use this design
Describe the information provided by main effects and interaction effects in a factorial design
© 2012 The McGraw-Hill Companies, Inc.
Describe an IV x PV design Discuss the role of simple main effects in
interpreting interactions Compare the assignment of participants in an
independent groups design, a repeated measures design, and a mixed factorial design
© 2012 The McGraw-Hill Companies, Inc.
Provides more information about the relationship than a two level design
Can provide us with a curvilinear relationship Inverted-U
Comparing Two or More Groups i.e. How dogs, cats, and birds, as opposed to
dogs alone, have beneficial effects on nursing home residents
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
Factorial Designs: Designs with more than one independent variable (or factor)
Simplest Factorial Design 2 x 2 factorial design
Has two independent variables Each independent variable has two levels
© 2012 The McGraw-Hill Companies, Inc.
Interpretation of Factorial Designs Main effects of an independent variable Interaction between the independent variables
Factorial Designs with Manipulated and Non-manipulated Variables IV x PV designs
(Independent Variable by Participant Variable)
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
Interactions and Moderator Variables Outcomes of a 2 x 2 Factorial Design
1. There may be a significant main effect for independent variable A
2. There may be a significant main effect for independent variable B
3. There may be a significant interaction between the independent variables(See results in following slides)
Interactions and Simple Main Effects Simple main effect of type of questioner Simple main effect of type of question
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
Assignment Procedures and Factorial Designs Independent groups design Repeated measures design Mixed factorial design using combined
assignment
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
© 2012 The McGraw-Hill Companies, Inc.
Increasing the Number of Levels of an Independent Variable
Increasing the Number of Independent Variables in a Factorial Design Repeated measures Mixed factorial design using combined
assignment
© 2012 The McGraw-Hill Companies, Inc.