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. 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.

We can infer a cause-and-effect relationship because multiple variables were included.

We cannot infer a cause-and-effect relationship because the treatments imposed were not blocked correctly.