Designing and Executing a Small Experiment

The purpose of this group assignment (groups of 4-5) is to allow participants to quickly design an experiment, gather data, and analyze the results.  The only conceivable way this can be done within a single semester is if the experiment is a simple, straight-forward replication of a published experiment.

First, therefore, find a relatively simple experiment in the literature of your choice.  If at all possible, it should have pre-established, pre-validated measurement scales for the experimental instrument.  The experimental procedures should be likewise simple enough that you can gather enough data from classes you are teaching or from those of your colleagues during the middle weeks of the term.  If you find a larger experiment that you can scale back so that it becomes feasible, that is also acceptable.

Second, fill out an Institutional Review Board form, and submit it for approval as soon as possible.  Go to: http://www.gsu.edu/~wwwosp/forms/entireIRB.pdf 

Third, gather data.  Be sure to have the subjects fill out the "informed consent" form.  Whether the experiment you are basing yours on did so or not, include a manipulation check for each of the treatments.  Debrief the subjects without revealing the hypotheses.

Fourth, analyze your data using ANOVA, ANCOVA, MANOVA, or MANCOVA.  Also, if the design is a 2x2x2 or less, run a regression on the same factors, using dummy variables for the treatments.

Fifth, write a report with the following sections.

1. Introduction

2. Short Literature Review, especially focusing on the experiment being replicated

3. Methods, mentioning if the original instruments were altered, if new variables or treatments were added, etc.

4. Data Analysis, including:

   • Instrument validation (re-validation) using Principal Components Analysis (PCA) and Cronbach's alpha

   • Results of manipulation checks

   • Results of statistical conclusion validity and hypothesis testing

   • Analysis of the power of your tests

5. Conclusion

Deliverable: Minimum 4-5 page report with sections above in it. Worth 48% of your grade. Oral presentations in class will be part of the overall grade.