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?
The solution provides step-by-step method of performing a ANOVA Analysis in EXCEL. All the steps of hypothesis testing (formulation of null and alternate hypotheses, selection of significance level, choosing the appropriate test-statistic, decision rule, calculation of test-statistic and conclusion) have been explained in details.