A research study was conducted to examine the clinical efficiency of a new antidepressant. Depressed patients were randomly assigned to one of three groups: a placebo group, a group that received a low dose of the drug, and a group that received a moderate dose of the drug. After four weeks of treatment, the patients completed the Beck Depression Inventory (BDI). The higher the score, the more depressed the patient. The data are presented below. Compute the appropriate test using a 0.05 significance level.
|
Placebo
|
Low Dose
|
Moderate Dose
|
|
38
|
22
|
14
|
|
47
|
19
|
26
|
|
39
|
8
|
11
|
|
25
|
23
|
18
|
|
42
|
31
|
5
|
1. What is your computed answer?
2. What would be the null hypothesis in this study?
3. What would be the alternate hypothesis?
4. What was the critical F value chosen?
5. Is there a significant difference between the groups?
6. Interpret your answer.