1. Types of Group Designs
_________-subject design. The experiment compares _____ group across different levels of the IV.
e.g., behavior is studied in 1 group that is given placebo, low, medium, and high doses of alcohol.
Lect 10c

2. WITHIN-SUBJECTS DESIGNS
Within-subject design:
Sometimes called a _______________design
_____ large group
Random selection (usually)
All subjects experience _____ conditions
No _________________treatment
_______ exposure to conditions - no stability
___________ statistics used to analyze mean effects
Subjects may not experience conditions in the same ______
Can involve 2 or _____ levels of the IV
Lect 10c

3. Within-subject design, single factor
Group A:
Level 1
of IV
Level 2
Same group examined under ____ levels of IV
Data usually analyzed used _____________
Lect 10c

4. Within-subject, multilevel-designs
Group A:
Level 1
of IV
Level 2
Level 3
Same group examined under ____________ of IV
Data usually analyzed used repeated-measures ______.
Example: Craik and Tulving (1975) investigated whether different word-processing strategies affected memory. Asked questions before showing subjects words. Questions focused on visual properties, auditory properties, and semantic properties. (18%, 78%, 96%)
Lect 10c

5. How do within-subject design differ from a single-subject design?
Repeated measures within each condition
Conditions run until _____
Each participant’s behavior is evaluated against their ____ behavior under other conditions
Individualized treatment
______ analysis of data
Within-subject design
_______ n
One measure under each condition
____ exposure to condition
A group’s average behavior under a condition is evaluated against the ____ group’s average behavior under other conditions
No individualized treatment
_____ analysis of data
Lect 10c

6. How do within-subject design differ from a single-subject design?
IV level 1
IV level 2
IV level 3
Single-subject
design
Subject #1
Subject #1
Subject #1
IV level 1
IV level 2
IV level 3
Within-subject
design
Group #1
Group #1
Group #1
Lect 10c

7. How do within-subject design differ from a between-subject design?
Moderate n
____ group
A group’s average behavior under each condition is evaluated against the same group’s average behavior under other conditions
Between-subject design
Large n
______ groups
Average behavior of a group exposed to one condition is evaluated against the average behavior of another group exposed to a different condition
Lect 10c

8. How do within-subject design differ from a between-subject design?
IV level 1
IV level 2
IV level 3
Between-subject
design
Group #1
Group #2
Group #3
IV level 1
IV level 2
IV level 3
Within-subject
design
Group #1
Group #1
Group #1
Lect 10c

9. WITHIN-SUBJECTS DESIGNS
Advantages of Within-subject designs over Between-group designs:
Main advantage ---Eliminates problems of individual ___________
Individual differences between groups cannot confound the study
You can measure treatment effects independent of individual differences
Fewer _____________ than between group
Lect 10c

10. WITHIN-SUBJECTS DESIGNS
Disadvantages of Within-subject designs:
___________
______-related problems
History, Maturation, Instrumentation, Statistical regression
________ effects – behavior may be influenced by earlier experiences in the study
__________ effects- changes in behavior caused by earlier treatment condition
__________________ – behavior changes as a function of experience - repeated testing (practice and fatigue)
Lect 10c

11. WITHIN-SUBJECTS DESIGNS- _____________________
Method of dealing with time-related threats
Subjects receive treatments in a ______ order
e.g., Reverse counterbalancing: AB, BA
e.g., Complete counterbalancing: In a study with 3 conditions (A, B, C) subjects may be exposed to: ABC, ACB, CBA, CAB, BCA, or BAC
_____ numbers of participants get each possible sequence
Prevents order effects from __________________ particular condition
Lect 10c

12. Treatment 1 Treatment 2 First Second Mean =20 Mean =26
No order effect
Treatment 1
Treatment 2
First
Second 20 27 23 29 25 19 26 31 17 22 14 16 24
Mean =20
Mean =26
6 pt difference

13. No order effect Order effect (+ 5) Treatment 1 Treatment 2 First
Second 20 27 23 29 25 19 26 31 17 22 14 16 24
Mean =20
Mean =26
Treatment 1
Treatment 2
First
Second 20
32 (27+5) 23
34 (29+5) 25 19
31 (26+5) 26
36 (31+5) 17
27 (22+5) 14
25 (20+5) 16
29 (24+5)
Mean =20
Mean =31
6 pt difference
11 pt difference

14. Order effect without counterbalancing Order effect with
Treatment 1
Treatment 2
First
Second 20
32 (27+5) 23
34 (29+5) 25 19
31 (26+5) 26
36 (31+5) 17
27 (22+5) 14
25 (20+5) 16
29 (24+5)
Mean =20
Mean =31
Treatment 1
Treatment 2
First
Second 20
32 (27+5) 23
34 (29+5) 25 19
31 (26+5) 31
22 (17+5) 22
19 (14+5)
21 (16+5) 24
Mean =22.6
Mean =28.5
11 pt difference
6 pt difference

15. Problems with counterbalancing
Can increase _____________ within a treatment
Different treatments may produce different order effects – _________________ order effects.
Complete counterbalancing requires ______________
May use _____ counterbalancing to at least ensure that each condition is experienced by a group first, second, third, etc.
Lect 10c

16. Summary of Single-Factor (one IV) Group Designs
Between-subject designs
2 levels
Multilevel
Control-group designs
Pretest-posttest control group design
Posttest only control group design
Solomon 4-group design
Within-group designs
Lect 10c