ANOVA for Comparing Depression Score

As part of a long-term study of individuals 65 years of age or older, sociologists and physicians at the Wentworth Medical Center in upstate New York conducted a study to investigate the relationship between geographic location and depression. A sample of 60 individuals, all in reasonably good health, was selected; 20 individuals were residents of Florida, 20 were residents of New York, and 20 were residents of North Carolina. Each of the individuals sampled was given a standardized test to measure depression. The data collected follow; higher test scores indicate higher levels of depression. These data are available on the data disk in the file MEDICAL I.

Fl New York North Carolina
3 8 10
7 11 7
7 9 3
3 7 5
8 8 11
8 7 8
8 8 4
5 4 3
5 13 7
2 10 8
6 6 8
2 8 7
6 12 3
6 8 9
9 6 8
7 8 12
5 5 6
4 7 3
7 7 8
3 8 11

A second part of the study considered the relationship between geographic location and depression for individuals 65 years of age or older who had a chronic health condition such as arthritis, hypertension, and/or heart ailment. A sample of 60 individuals with such conditions was identified. Again, 20 were residents of Florida, 20 were residents of New York, and 20 were residents of North Carolina. The levels of depression recorded for this study follow. These data are available on the data disk in the file MEDICAL 2.

Fl NY North Carolina
13 14 10
12 9 12
17 15 15
17 12 18
20 16 12
21 24 14
16 18 17
14 14 8
13 15 14
17 17 16
12 20 18
9 11 17
12 23 19
15 19 15
16 17 13
15 14 14
13 9 11
10 14 12
11 13 13
17 11 11

1. Use descriptive statistics to summarize the data from the two studies. What are your preliminary observations about the depression scores?
2. Use analysis of variance on both data sets. State the hypotheses being tested in each case. What are your conclusions?
3. Use inferences about individual treatment means where appropriate. What are your conclusions?
4. Discuss extensions of this study or other analyses that you feel might be helpful.