In a Recent Study, Researchers Followed 104,000 U

Short Answer

In a recent study, researchers followed 104,000 U.S. veterans who had served in the armed forces and a comparison group of 216,000 nonveterans. Over a period of 12 years, they found that 197 veterans and 311 nonveterans committed suicide.
a. Identify the explanatory and response variables in this study.
Explanatory:
Response:
b. Is this an observational study or an experiment? Explain briefly.
c. Calculate the proportion who committed suicide in the veterans group. Then do the same for the nonveterans group.
Veterans group:
Nonveterans group:
d. The study also found that overweight people were much less likely to commit suicide than underweight people. Would you conclude that weight gain causes a lower risk of suicide? Explain briefly.
e. Following the point about overweight people being less likely to commit suicide, the researchers said that smoking may be a confounding variable, however. Explain what this statement means in the context of this issue.