LR Question 9 Explanation
QUESTION TEXT: Cereal advertisement: Fitness experts say that regular…
QUESTION TYPE: Flawed Reasoning
CONCLUSION: Fantastic flakes cereal makes you run!
REASONING: People who eat cereal tend to run more than those who don’t.
ANALYSIS: This confuses correlation for causation. In any situation of correlation, there are always multiple possibilities:
- Running makes you more likely to eat cereal.
- Cereal makes you more likely to run.
- A third factor (such as a healthy lifestyle) makes you both eat cereal and run.
The advertisement incorrectly assumes that the second possibility is true, without proof. But it could be that runners choose cereal, or runners get hungrier, etc.
___________
- CORRECT. See the analysis above. Just seeing that two things happen together doesn’t mean that one causes the other.
- The argument didn’t compare Fantastic Flakes to any other cereals!
- This is a different flaw.
Example of flaw: Sleeping well contributes to a good LSAT score. So, if you sleep well and do nothing else, you will get a good LSAT score. - The sample size isn’t mentioned. When no sample is mentioned on the LSAT, you can generally assume the sample was big enough – the questions don’t have enough space to explicitly describe samples each time. So when they say “studies have shown that adults” they mean large studies of adults in general.
Example of flaw: We studied adult firefighters at a single firestation in a small town. So, we know what all Americans do. - This is a part to whole flaw. It’s different.
Example of flaw: Americans are generally patriotic. So this individual American, Benedict Arnold, was a patriot.
More Resources for Flaw Questions
- Flaw drills: Use these to practice making examples of abstract flaws.
- Intro Course lesson: This intro course lesson covers Flaw questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers flaw questions.
One thing that made me contemplate E was that they went from talking about how cereal contributes to exercise, and the conclusion narrows it down to “Fantastic Flakes”. Any elaboration of how this is not a part to a whole error?
First of all, it’s whole to part (cereal to fantastic flakes.). And, Whole to part isn’t always an error. If I say “Knives kill you if they stab people in the heart”. Then it is a valid conclusion to say “Therefore this hunting knife kills if it stabs a person in the heart”.
The real problem is the reversal of causation and correlation when considering cereal and exercise.