Passage Summary: People who check nutrition labels eat less fat, so the author concludes that the act of reading the labels is what makes them eat better.

Conclusion: Reading nutrition labels causes people to adopt healthier dietary habits.

Reasoning: There is a statistical correlation showing that people who read food labels consume a lower percentage of fat calories than those who do not.

Analysis: This is a classic case of confusing correlation with causation. The author observes two things happening together—label reading and low-fat diets—and assumes the first causes the second. However, it is just as likely that people who are already health-conscious are the ones who bother to read labels in the first place. Look for an answer that points out the failure to consider that a third factor might be responsible for both behaviors.