Fibromyalgia (FMS) and chronic fatigue syndrome (CFS) are two illnesses that often coexist. Patients who have both

Question:

Fibromyalgia (FMS) and chronic fatigue syndrome (CFS) are two illnesses that often coexist. Patients who have both illnesses tend to suffer from fatigue, poor sleep, lack of mental clarity, and body aches. Researchers randomly assigned 69 patients with both FMS and CFS and 3 patients with only FMS to a treatment group and a control group. The treatment group took low dosages of a large number of medications and the control group took placebos. At each of four monthly visits, the individuals rated their energy, sleep, mental clarity, degree of feeling pain-free, and overall sense of well-being each on a scale of 0 to 100, for a total possible €œwell-being€ score of 500 points. The mean well-being scores for both groups are shown in Table 25 for the four visits.

a. Construct a scatterplot that describes the association between the visit number and the mean well-being score (in points) for the treatment group. Do the same for the control group. Show both scatterplots in the same coordinate system if you know how to use colors or shapes to identify which points are for which group.
b. During the study, did the treatment group€™s mean well- being score increase more, less, or about the same as the control group?
c. Let s be the mean well-being score for the treatment group at the nth visit. Find an equation of a linear model that describes the association between n and s.
d. What is the slope of the treatment-group model? What does it mean in this situation?
e. Use the model to predict what the treatment group€™s well- being score would have been if it had visited 10 times. Has model breakdown occurred? Explain.