1. Procedure for Conducting an Experiment
Chapter 9
Procedure for Conducting an Experiment
ch12(1)

2. Institutional Review Boards (IRBs)
All research involving human subjects must be approved by IRB.
Primary concern is the welfare of the participants.
ch12(1)

3. Research Protocol – detailed description of a study.

4. Risk/Benefit analysis - IRB boards decision is final!
ch12(1)

5. External validity – to whom and in what circumstances do the results of the study apply. External validity is not a design issue. It is a questioned that needs to be addressed in interpreting and using the findings of the study.
ch12(1)

6. Animal Research in Medicine
External validity here depends on how good a Model the biological systems on the animal is of the human system.
ch12(1)

7. Behaviorist and the Rats: What’s up with that?
ch12(1)

8. Research Participants Inclusion and Exclusion Criteria
Convenience Samples – use who is available!
- General Psychology Research Pool.
ch12(1)

9. Convenience and Availability Samples Volunteer Problem
Importance of Random Assignment with
Convenience Samples.
ch12(1)

10. Problems using non-college Populations
Special Populations (Children, Prisoners, Elderly, mentally or psychologically impaired.
Permission must be granted from every possible legal stakeholder.
ch12(1)

11. Kids? Who has to approve it?
Want to study these
Kids? Who has to approve it?
School Board
School Principal
Teacher
Parents (Active Informed Consent)
Child (Assent)
ch12(1)

12. Social Psychology Network American Psychological Association
Internet Research
Social Psychology Network
American Psychological Association
ch12(1)

13. We want high power in our study. Approx 0.8
Power – probability of rejecting a false null hypothesis.
Probability of detecting a difference between conditions when one exists.
We want high power in our study.
Approx 0.8
What does Power of 0.8 mean?
ch12(1)

14. Effect Size – Correlation between IV and DV.
Tells you how well you can predict the DV, if you know the participant’s IV condition.
e.g., If I know whether a person is male or female, how much does that improve my ability to predict their math ability.
Cohen’s (1992) Criteria.
Effect size or .10 is small, .30 is moderate and .50 is large.
ch12(1)

15. The larger the Effect Size is the more Power the study has.
Very Powerful studies can find significant (not due to chance) effects that are very small.
Studies with low power may be unable to detect even large effects of the IV
ch12(1)

16. Alpha Level: Chance we are willing to take of making a Type I error.
If we change alpha to .10, we would correctly accept a lot more comparisons as significant, but we will also greatly increase our chance of making a type one error.
ch12(1)

17. Sample Size, Power and Effect Size are
Related in such a way that if you know two of these values for a study, you can
determine the third (from a chart) for a given alpha level.
ch12(1)

19. ↑ Sample Size ↑ Power
↑ Effect Size ↑ Power
↑ Alpha ↑ Power
ch12(1)

20. Apparatus and /Instructions
ch12(1)

21. Instructions (Protocol)
Procedure
Instructions (Protocol)
All subjects receive the same instructions with the exception of changes needed to
manipulate the IV.
Scheduling Participants.
Time of Day Interactions
Running in Groups or Individually
ch12(1)

22. - wording or the instructions - practice for the experimenter
Pilot Studies
- tests the procedure
- wording or the instructions
- practice for the experimenter
- run through for equipment and
computer programs
ch12(1)

23. Debriefing (Post Experimental Interview) Functions Ethical
- undo deception
- undo stress
Educational Function
Post experimental Inquiry
Satisfaction
ch12(1)