Factorial Design Worksheet
1. Consider the data below from a factorial-design experiment. The DV was “# of
participants who offered to help a stranger in distress.”
Gender of Stranger
Number of bystanders
0
10
Male
30
10
Female
90
50
a. What is the design of this study? (e.g., 2x2, 3x2, 2x3x2, etc.)
b. List the independent variables in the study and then list the levels of each IV.
c. Sketch a graph of the results of the study and fill in names and levels of each IV.
% of Participants Who Helped Stranger in
Distress
100
90
80
70
60
50
Male Stranger
40
Female Stranger
30
20
10
0
0
10
Number of Bystanders
d. Main effects
 On average (collapsing across gender of the stranger) how does number of
bystanders affect helping behavior?

On average (collapsing across number of bystanders) how does the gender of
the stranger affect helping behavior?
2. Consider the data below from a factorial-design experiment. The DV was # of
hallucinations.
Type of Drug
Dose of drug
Low
Medium
High
LSD
4
6
13
Marijuana
1
2
3
a. What is the design of this study? (e.g., 2x2, 3x2, 2x3x2, etc.)
b. List the independent variables in the study and then list the levels of each IV.
c. Sketch a graph of the results of the study and fill in names and levels of each
IV.
15
14
13
Number of Hallucinations
12
11
10
9
8
LSD
7
Marijuana
6
5
4
3
2
1
0
Low
Medium
High
d. Main effects
 On average (collapsing across type of drug) how does drug dose affect
number of hallucinations?

On average (collapsing across drug dose) how does type of drug affect
number of hallucinations?

Do the graphed data suggest the presence of an interaction effect, if so
describe it.
3. Design your own 2x2 study on a topic of interest to your group.
a. What is your first IV and the levels?
b. What is your second IV and the levels?
c. What is your DV?
d. Draw a graph of your expected results.
e. Do you have a main effect of your first IV?
f. Do you have a main effect of your second IV?
g. Do you have an interaction?