PSYC*2360 Chapter 12: Mixed Design

Question 1

What is a single-subject design?

Answer 1

A type of within-subjects design using one participant or one group to assess changes within that individual or group

Question 2

What is a single-subject design also known as?

Answer 2

• A single-case experimental design
• A single-n design

Question 3

What are three types of single-subject designs?

Answer 3

• The A-B design
• The A-B-A design
• The A-B-A-B design

Question 4

What are the two phases of an A-B design?

Answer 4

-Phase A: Take baseline measurement
- Phase B: Introduce intervention or experimental treatment and take measurement again

Question 5

T or F: The change in measurement from the A phase to the B phase might suggest a causal relation.

Answer 5

True

Question 6

In an A-B design, what might the second measure (B) be more easily influenced by?

Answer 6

Extraneous factors

Question 7

What are the three phases of an A-B-A design?

Answer 7

• Phase A: Take baseline measurement
• Phase B: Introduce intervention or experimental treatment and take measurement again
• Phase A: Remove the intervention and take the measurement again

Question 8

How does an A-B-A design help establish covariation?

Answer 8

By showing that behaviour systematically changes as researchers introduce and remove treatment

Question 9

What are the four phases of an A-B-A-B design?

Answer 9

• Phase A: Take baseline measurement
• Phase B: Introduce intervention or experimental treatment and take measurement again
• Phase A: Remove the intervention and take the measurement again
• Phase B: Reintroduce intervention and take measurement again

Question 10

Which type of single-subject design provides the best evidence of causality?

Answer 10

The A-B-A-B design

Question 11

What are two weaknesses of single-subject designs?

Answer 11

• No control group
• Low external validity/ability to generalize findings

Question 12

T or F: Some argue that the participant/group serves as the control group whenever the treatment is removed in an A-B-A or A-B-A-B design.

Answer 12

True

Question 13

What is a mixed design?

Answer 13

An experimental design that combines within-subjects and between-subjects methods of data collection

Question 14

T or F: In a mixed design, all participants receive every level of the between-subjects factor, but only one level of the within-subjects factor.

Answer 14

False. All participants receive every level of the WITHIN-subjects factor, but only one level of the BETWEEN-subjects factor.

Question 15

What are two benefits of mixed designs?

Answer 15

• The strengths of a within-subjects design help compensate for the weaknesses of the between-subjects design and vice versa
• Allows the research to answer more than two questions (main effects of each IV and interaction effects between IVs)

Question 16

What is the main strength of a between-subjects design?

Answer 16

High internal and external validity

Question 17

What is the main weakness of a between-subjects design?

Answer 17

Low power

Question 18

What is the main strength of a within-subjects design?

Answer 18

High power

Question 19

What is the main weakness of a within-subjects design?

Answer 19

Low internal and external validity

Question 20

What are two types of control groups commonly used in clinical research?

Answer 20

• Treatment-as-usual group
• Waiting-list group

Question 21

What is a treatment-as-usual control group?

Answer 21

A group in which an already established treatment is administered for comparison to the experimental treatment

Question 22

What is a waiting-list control group?

Answer 22

A control group in which participants don’t receive any treatment of intervention until after the completion of the study

Question 23

Are baseline measures taken from the waiting-list control group?

Answer 23

Yes

Question 24

T or F: Once the study’s results are clear and the best form of intervention is identified, participants in the waiting-list control have the first opportunity to receive the best treatment, but must still pay.

Answer 24

False. They receive the treatment at no cost.

Question 25

What is the experimenter-expectancy effect?

Answer 25

When a bias causes a researcher to unconsciously influence the participants

Question 26

What is the experimenter-expectancy effect also known as?

Answer 26

• Expectancy bias
• Experimenter bias

Question 27

What is one way to reduce the experimenter-expectancy effect?

Answer 27

Use a double-blind procedure

Question 28

What is a double-blind procedure?

Answer 28

A protocol in which neither the participants nor the administrators of treatment are aware of which treatment is being provided

Question 29

What is a single-blind procedure?

Answer 29

A protocol in which the participants are unaware of which treatment they are receiving, but the administrator knows

Question 30

How can bias be minimized in a single-blind procedure?

Answer 30

By not sharing the hypothesis

Question 31

Which statistical analysis tests for differences between two or more categorical independent variables, where at least one is a between-subjects variable and another is a between-subjects variable?

Answer 31

A mixed design ANOVA

Question 32

A mixed design ANOVA can be described as a combination of what two statistical tests?

Answer 32

A repeated-measures ANOVA and a factorial ANOVA

Question 33

When presenting the findings from a mixed design ANOVA, what are the two values in the parentheses that follow F (F(X, Y)=)?

Answer 33

• X= Between-subjects degrees of freedom
• Y= Within-subjects defrees of freedom