"Early Television Exposure and Subsequent Attentional Problems in Children," published in Pediatrics in April 2004, investigated television-watching habits and subsequent rate of hyperactivity for a large group of children.
a. Was this an experiment or an observational study? How do you know?
b. The study found that "A 1-SD increase in the number of hours of television watched at age 1 is associated with a 28% increase in the probability of having attentional problems at age 7."25 Can you describe another possible explanation for this result, besides the obvious cause-and-effect that the researchers had in mind?
c. The results summarized in part (b) suggest that television watching was handled as a quantitative variable, and behavior as categorical. Which of these plays the role of explanatory variable?
d. Suppose that television really does not cause hyperactivity, and the results observed were only due to confounding variables. If this were the case, and researchers had made claims of causation, would they have been committing a Type I or a Type II Error?