Passage Summary: The average person is making more money now than five years ago, and since the Andersens are average now, they must have personally seen a raise.

Conclusion: The Andersen family's real income must have increased over the last five years.

Reasoning: The average family income has risen over the last five years, and the Andersen family currently earns the average income amount.

Analysis: This argument commits a classic error by confusing a group's longitudinal trend with an individual's personal history. Just because the 'average' is higher now doesn't mean every person currently at that average reached it by moving upward; the Andersens could have been wealthy five years ago and lost money to drop down to the current average. It's a bit like saying because the average height of a class increased, the new kid who is average height must have hit a growth spurt. Look for an answer that points out the family's past income is not necessarily determined by the current national average.