Chapter 7—Single-Factor Designs

Question 1

What is a single-factor design?

Answer 1

A genre of research designs with one IV—used in both double and multilevel designs

Question 2

Describe the four single-factor designs

Answer 2

1. Independent group designs:
   —> between subjects
   —> manipulated IV
   —> RA used to create equivalent groups
2. Matched groups design:
   —> between subjects
   —> IV is manipulated
   —> Matching and then RA is used to create equivalent groups
3. Ex post facto design:
   —> between subjects
   —> quasi-experimental
   —> IV is a subject variable (no RA)
   —> Matching may increase equivalence between groups
4. Repeated-measures design:
   —> within subjects
   —> IV is manipulated
   —> 2 levels, limited counterbalancing options. 3+, all opt

Question 3

How do we test for single factor designs?

Answer 3

We use T-Tests: examine the difference in means between the 2 samples and determines whether the difference is significantly more than chance

Question 4

Describe the two kinds of t-tests

Answer 4

Independent sample t-test:
—> between-subjects
—> independent groups design; Ex post facto design
—> when the two groups are completely separate
Dependent samples t-test:
—> within-subjects
—> Matched groups design
—> Repeated-measures design

Question 5

What is a single-factor multilevel design? What is their main advantage?

Answer 5

Designs where the IV has more than 3 levels

Main advantage: enables researchers to discover nonlinear effects

Question 6

How do we test for single factor designs with multiple levels?

Answer 6

One way ANOVAs: tests for the for the presence of an overall significant effect that could exist somewhere between the levels of the IV

Question 7

What is an F-score?

Answer 7

Examines the extent to which the obtained mean differences are due to chance or the IV

Question 8

What 3 ways do we present the data of a single factor design, and when?

Answer 8

1. Presenting numbers in sentence form; fine for reporting results of studies w 2-3 levels
2. Table: preferred when data points are so numerous that a graph would be uninterpretable
3. Graph: good for nonlinear effects or interactions

Question 9

What is systematic variance?

Answer 9

What a study hopes to find; real, meaningful differences between conditions/groups. Variance in DV that can be explained by the IV

Question 10

What is error variance?

Answer 10

What a study hopes to NOT find; variance in the DV that cannot be attributed to the IV.

Question 11

What is the homogeneity of variance?

Answer 11

the assumption that the amount of variability (i.e., spread or dispersion) in the dependent variable is roughly equal across all groups or conditions being compared.

Question 12

What is a waitlist control group?

Answer 12

a type of control group used in applied or clinical research where participants don’t receive the treatment right away, but are promised it after the study ends.

Question 13

Describe the Yoked control group design

Answer 13

Each control participant is “linked” (or yoked) to a participant in the experimental group

Experimental group: participants receive a treatment or condition based on their own behaviour

Yoked control group: each person receives the same treatment as the person they’re paired to, but not as a result of their own behavior—just because their counterpart did

Helps test if control or choice matters beyond just getting the reward.