The results of a recent study showed that children who routinely drank reduced fat milk (1% or skim) were more likely to be overweight or obese at ages 2 and 4 compared to children who drank whole or 2% milk (Scharf, Demmer, & DeBoer, 2013).

a. Is this an example of an experimental or a nonexperimental study?

b. Explain how individual differences could provide an alternative explanation for the difference in weight between the groups.

c. Create a research study that would be able to differentiate among those interpretations of the results.