A study was conducted on the effects of long-term marriage (more than 10 years).
Researchers gathered data from a random sample of 4,563 adults and measured
quite a few variables, in addition to the explanatory variable of marriage and the
response variable of longer life span. According to a newspaper article summarizing
the study, those in long-term marriages were more likely to be more physically
active, at a healthy weight, and nonsmokers. Those who were not married were
about 20% more likely to be deceased. What conclusion can we draw from this
study? Explain.
D We can infer a cause-and-effect relationship because the sample was selected
randomly.
We cannot infer a cause-and-effect relationship because treatments were not
assigned randomly.
) We cannot infer a cause-and-effect relationship because we do not have a
control group.