PSYC 226- C12.2

Factorial Designs in Popular Press: look for phrases such as ___ to highlight an interaction

"it depends" and try to draw a line graph to figure out what is going on

Example of The Method

3x4 factorial design has two independent variables, one with 3 levels and the other with 4 levels. The number of experimental conditions is 3x4= 12

How many cells does a 2x3 factorial design have?

6 cells (6 conditions)

Example of a 2x2x2 design

Cell Phone Use (2 levels), Age (2 levels, and Traffic (2 levels)

"Effects of Cell Phone Conversations on Younger and Older Drivers": The Results

The MANOVA indicated significant main effects of age, F(4,35)= 8.74, p< .01. and single vs dual task, F(4,35)= 11.44, p< .01

Sometimes more than two independent variables are studied such as...

a 2x2x2 factorial design (8 experimental conditions)

Example of a Three-way Interaction asks...

are two-way interaction effects different at each level of the 3rd independent variable?

Factorial Designs in Empirical Articles: The Method

describes the study design

Factorial Designs in Empirical Articles: The Results

examines whether main effects and the interaction effect are statistically significant

Factorial Designs in Popular Press: which variables should tried to be identified?

factors and the dependent variable

RECALL: 2x2 factorial design has how many experimental conditions/cells?

four

Factorial Design: Independent-groups

in a 2x2 there are different participants in each of the four experimental conditions (ex. alcohol, body weight, and aggression)

Factorial Design: Within-groups

in a 2x2 there are the same participants in each of the four experimental conditions

Factorial Designs: Mixed

in a 2x2 there are the same participants with respect to one independent variable and different participants with respect to the other independent variable (ex. cell phone, age, and driving quality)

Two simple experiment designs:

independent-groups design and within-groups design

Types of Factorial Designs:

independent-groups, within-groups, mixed

"Effects of Cell Phone Conversations on Younger and Older Drivers": The Method

it was a 2 (age: younger vs older adults) x 2 (task: single vs dual task) factorial

The Results provides reference to:

significant or a p-value, information about the type of statistical analysis used (ex. ANOVA, ANCOVA, MANOVA, etc.) and test statistics evaluated (ex. t, F, etc.)

"Effects of Cell Phone Conversations on Younger and Older Drivers": The Results- was the interaction significant?

the Age x Single vs Dual-Task interaction was not significant, F(4,35)= 1.46, p> .23

Independent-groups design

with different participants in each experimental condition

Within-groups design

with same participants in each experimental condition

In a mixed factorial design the first factor is ___ and the second factor is ____

within-groups, between-groups

Within-groups Factorial Design is also called:

within-subjects factorial design