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-subject ANOVA or a within-subject 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?