medium · LSAT Logical Reasoning
A financial advisor reports that, among her clients, those who invested in index funds outperformed those who picked individual stocks, and she concludes that index investing is the superior strategy. An analyst objects that the comparison suffers from selection bias: the two groups were not randomly assigned but chose their own approaches, so the index investors may have differed from the stock-pickers in ways—such as patience or risk tolerance—that themselves explain the better returns.
Which one of the following best describes the 'selection bias' the analyst identifies?
- The advisor's data covers only a single year of performance rather than a full decade.
- The two groups being compared may already differ in pre-existing traits that account for the observed outcome.
- The term 'outperforming' is not applied consistently from one client to the next.
- The conclusion rests on the advisor's own track record rather than on the funds' returns.
- The clients who invested in index funds were far more numerous than those who picked stocks.
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More LSAT Logical Reasoning practice
- Which one of the following is an assumption required by the argument?
- Which one of the following can be properly inferred from the statements above?
- The question type just described is best identified as which one of the following?
- The reasoning in the argument is flawed in that the argument
- The reasoning in the argument is flawed because the argument
- Which one of the following most accurately describes the relationship the statement establ
- Which one of the following can be validly inferred from the two conditionals above?
- Which one of the following must be true given the statement above?