A Columbia University Study Linked Soda Consumption to Behavior Problems

Multiple Choice

A Columbia University study linked soda consumption to behavior problems in children.
Researchers examined data from a previous study that followed 2929 mother-child pairs. One survey asked about behaviors of the child and also about soda consumption. They found that the
More soda the kids drank, the more behavior problems they had. What aspect of a well-designed experiment is absent from this study?

A) a placebo
B) all of these
C) blinding
D) randomization
E) a control group