LSAT 37, Logical Reasoning I, Q21

QUESTION TEXT: The studies showing that increased consumption of…

QUESTION TYPE: Flawed Parallel Reasoning

CONCLUSION: There is no increased health risk from eating fruits and vegetables that had pesticides.

REASONING: Some studies show that eating fruits and vegetables decreases the risk of cancer. The studies did not separate organic fruit and vegetables and those that had pesticides. 

ANALYSIS: The conclusion is about health risks while the evidence is about cancer risk. The argument confuses two types of risk. 

There’s another error. The study mixed up the organic and non-organic fruits and vegetables. Overall, fruits and vegetables reduce cancer risks. 

But if we separate non-organic from organic, it’s possible that non-organic fruits and vegetables would increase health risks, while organic varieties decrease them.

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1. CORRECT. Modern power plants decrease the incidence of certain diseases. But the conclusion says that nuclear power plants do not present an overall risk to health. Health includes all diseases.
   This also repeats the error of lumping together both groups into one study, then assuming that what is true of the whole group is true of each part.
2. This is a bad argument. It has proven that either exercise or diet could work. But it hasn’t proven which strategy is more useful. Yet the argument doesn’t make the error in the stimulus of confusing two terms.
3. This is a bad argument. Motorcyclists receive one year of instruction while car drivers just pass a test. One would hope a year of training would make motorcyclists safe. But this argument doesn’t make the error of confusing two types of risk.
4. This is a bad argument. We don’t necessarily care whether a cutting board has fewer microbes. We care whether it has fewer microbes that are harmful. There are microbes everywhere, and most don’t hurt us. But this argument doesn’t confuse two types of risk.
5. This is a good argument. Lack of a health benefit to doing something means there is no health risk to not doing it. 

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