Scenario: Imagine that a psychologist working with veterans withpost-traumatic stress disorder wants to compare the effectivenessof several therapies focused on reducing symptoms of anxiety. Thepsychologist randomly sampled 20 veterans who recently returnedfrom combat and randomly assigned each of them to receive one offour interventions for 8 weeks. A survey was used to measure theparticipants’ anxiety at the end of the 8 weeks. Higher anxietyscores indicate more anxiety.

Use SPSS to comparethe mean anxiety scores with a one-way ANOVA.

1. Before computing any analyses, state the null hypothesis andalternative hypothesis in words (not formulas).
2. Identify the factor and dependent variable.
3. Name the levels of the factor.
4. State the degrees of freedom between groups and explain how youcalculated it by hand.
5. State the degrees of freedom within groups and explain how youcalculated it by hand.
6. Identify the obtained F value using SPSS and report it in youranswer document.
7. Identify the p value using SPSS and report it in your answerdocument.
8. Explain whether the F test is statistically significant.Explain how you know.
9. Explain what the psychologist can conclude about therelationship between different types of therapy and anxiety.
10. Should the psychologist conduct a post hoc test? Why or whynot? If post hoc testing is needed, conduct a Tukey HSD post hocanalysis in SPSS. Explain what the results tell you.

• Anxietyscores for 5 veterans who received behavioral therapy
108
109
107
105
106
• Anxiety scores for 5veterans who received cognitive therapy
105
102
104
102
106
• Anxiety scores for 5veterans who received biofeedback therapy
101
102
105
100
101
• Anxiety scores for 5veterans who received medication therapy
101
104
103
105
103