Lecture 12

Question 1

Factorial Experiments

Answer 1

Experimental designs in which 2 or more independent variables are manipulated at the same time (these permit the examination of interactions)

Question 2

Advantages of Factorial Designs

Answer 2

1. Joint manipulation of independent variables
2. Interaction
3. Saves time, money, and effort by doing one bigger experiment (2 or more independent variables) than several smaller experiments.

Question 3

Main Effects

Answer 3

The separate effect of each independent variable AVERAGED over the levels of the other independent variable (AVERAGED EFFECTS).
EX…Psychotherapy (CBT, BT, & Waitlist) vs. Medication (No Meds, Half-dose, & Full Meds)

Question 4

Simple Effects AKA Simple Main Effects

Answer 4

The variability among the treatment means are associated with one independent variable (Psychotherapy) at a particular level of the other independent variable (Medication)

Question 5

Interaction

Answer 5

When the effect of one of the independent variables on the dependent variable is not the same at all levels of the second independent variable.

The main effect is NOT representative of the corresponding simple effects and does not accurately describe the data.

Question 6

Factorial Design

Answer 6

1. Between-Subjects Factorial
2. Within-Subjects Factorial
3. Mixed Factorial

WSD: Highest power, no individual differences, smallest number of subjects, largest carryover effects

MSD: Middle power, middle individual differences, middle number of subjects, middle carryover effects

BSD: Lowest power, largest individual differences, largest number of subjects, no carryover effects