Recent research indicates that the effectiveness of antidepressant medication is

Question

Recent research indicates that the effectiveness of antidepressant medication is directly related to the severity of the depression (Khan, Brodhead, Kolts & Brown, 2005). Based on pre-treatment depression scores, patients were divided into four groups based on their level of depression. After receiving the antidepressant medication, depression scores were measured again and the amount of improvement was recorded for each patient. The following data are similar to the results of the study. Use a significance level of = 0.01. Assume depression scores are normally distributed with constant variance and test to see if there is a difference in the mean scores. Round answers to at least 4 decimal places. High Moderately Low Moderate Moderate SevereSevere 5.6 1.3 0.9 1.2 4.4 1.8 1.4 2.1 2.9 2.4 3.8 2.7 4.4 2.9 2.6 3.9 3.6-2.2-4.8 2.9 2.6 0.2 2.1 1.6 2.1 2.2 1.6 2.7 2.5 3.6 4 4.3 2.6 3.8 3.6 4.7 4.1 3.5 4.2 2.5 2.4 0.7 2.3 1.4 2.7 4.6 0 2.2 2.1 3.1 2.3 1.8 2.9 1.5 1.2 2.5 4.7 3.9 3.4 3.6 5.9 3.7 4.2 2.5 3.7 3.2 2.7 0.2 2.6 3.7 3.4 2.2

Explanation / Answer

The statistical software output for this problem is:

Analysis of Variance results:
Data stored in separate columns.

Column statistics

ANOVA table

Hence,

Summary table for ANOVA:

Test statistic = 8.4301

P - value = 0.0000

Reject the null hypothesis.

Yes

Column n Mean Std. Dev. Std. Error Low Moderate 25 1.824 1.051697 0.21033941 High Moderate 25 2.6 0.8967534 0.17935068 Moderately Severe 25 3.192 1.1109005 0.22218011 Severe 25 3.152 1.3013198 0.26026397

Related Questions

Navigate

• Browse (All)
• Browse R
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.