Lab Activity 11: Understanding One-way ANOVA designs

Please read and answer the questions below.

In the following study, participants were randomly assigned to receive humanistic therapy, psychodynamic therapy, or behavioral therapy for their depression. Six months after therapy ended, participants' levels of depression were rated on a Likert scale from 1 (not at all depressed) to 15 (extremely depressed).

GROUPNMEANSTD DEVSTD ERROR

1 (humanistic)105.402.170.69

2 (psychodynamic)107.502.840.90

3 (behavioral)105.603.130.99

ONEWAY ANOVA: THERAPY by DEPRESSION

SUM OFMEAN

SOURCESQUARESDFSQUARESF RATIOPROB.

BETWEEN GROUPS26.87213.731.78.187

WITHIN GROUPS203.30277.53

TOTAL230.1729

POST HOC TEST: Tukey-HSD with significance level .05

*Indicates significant differences shown for pairings

GGG

rrr

ppp

123

MeanTHERAPY

5.40Grp 1

7.50Grp 2

5.60Grp 3

1. Is this a two-group design or a multiple-group design? How do you know?
2. This study is an independent groups design. How do you know?
3. How could you change this experiment to be a repeated measures design?
4. How could you change this experiment to be a matched sets design?
5. Is this a true experiment or an ex post facto study? How do you know?
6. What is the independent variable in this study?
7. What is the dependent variable in this study?
8. What is the scale of measurement for the dependent variable?
9. What kind of statistical analysis was conducted?
10. Did the independent variable have a significant effect on the dependent variable? How do you know?
11. Do a conclusion for these results. (APA)