Ch12: Experiment with More Than One Independent Variable

factorial design

when 2 or more independent variables are manipulated

factorial design example

2 IVs = 2-way factorial design

• Would have 2 main effects and 4 interactions (if each IV had 2 levels)

Name and describe the kinds of information received in a factorial design

• Main effect - effects of each IV; implies more than 1 IV

  • 1 main effect per independent variable

• Interaction - how does operation of 1 IV affect operation of another IV?

  • Number of interactions depends on number of IVs

notation process in a factorial design

(eg. 2 x 2; 2 x 2 x 3): [blank] x [blank] …

• The number of “blanks” is the number of independent variables

• Each individual number is the number of levels each IV has

  • ex. 2 x 3 - “Design a 2 x 3 study”

    • 2 independent variables

    • 1st IV has 2 levels

    • 2nd IV has 3 levels

    • 2 main effects; 6 interactions/groups