When you read published research studies, you will find that many are experimental studies in which
Question: When you read published research studies, you will find that many are experimental studies in which one or more variables are manipulated. An example is a study of whether students with windows in their classrooms give their instructors higher evaluations than students with no windows in their classrooms. You could compare these two groups with a t-test, which you studied in Week 4. Perhaps it would be more interesting to have additional levels of "scenery." You might compare instructor evaluations when students are in a class with no windows, a class with windows that look out to a parking lot, a class with windows that look out to a park, or a class with no windows but pictures of windows on the wall. Since you have multiple levels of the factor, scenery, you use an ANOVA instead of a t-test.
This assignment will give you practice interpreting a study with multiple levels of a factor. Since many research studies rely on the ANOVA for analysis, you will enhance your ability to understand the results of research studies that are of interest to you.
? Carefully review Chapter 13 in your text.
? Review the PowerPoint for Chapter 13.
? Consider the following study and data:
Katie is studying aggression among adolescent girls. She believes that there is a relationship between the level of interaction a girl has with her mother and her level of aggression. She has identified 5 girls who fall into each of 4 interaction levels and has measured their aggression scores. Her data are given below.
| No Interaction | Low Interaction | Moderate Interaction | High Interaction |
| 4 | 4 | 4 | 3 |
| 5 | 6 | 4 | 4 |
| 6 | 5 | 3 | 4 |
| 6 | 4 | 5 | 3 |
| 5 | 5 | 4 | 3 |
The summary table is as follows:
| Source | Sum of Squares | df | Mean Square | F |
| Between groups | 9.75 | 3 | 3.250 | 5.91 |
| Within groups | 8.80 | 16 | 0.550 | |
| Total | 18.55 | 19 |
? What are the independent variable and the dependent variables?
? Should Katie conduct a between-subjects ANOVA or a within-subjects ANOVA? Explain your answer.
? How many factors are involved in Katie's study?
? How many levels are involved? Name the level(s).
? What are the null and alternate hypotheses?
? Using a = 0.05, what is Fcrit?
? Is the F-test significant?
? Based on your answer about significance, what else should you do and why?
Deliverable: Word Document
