Logical reasoning PrepTest 111 · Section 4 · Question 24

Incorrect. The conclusion is about lowering cholesterol and heart disease, so potential side effects of pravastatin are out of scope. This answer would be relevant if the argument concluded that pravastatin should be prescribed, or increased overall health.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Background - Pravastatin lowers lowers cholesterol
Study - Those on pravastatin had fewer nonfatal heart attacks and deaths from heart disease than those who weren't on it
Other studies - Heart disease is correlated with high cholesterol levels
Conclusion - Lowering cholesterol reduces heart attack risk

Answer Anticipation:
This Errors in Reasoning question has two features that suggest specific flaws.

First, the fact that there's a study suggests there's a sampling flaw. However, 6,403 is certainly large enough, and there's no indication that the people were unrepresentative, so a sampling flaw is unlikely to play into the correct answer.

Second, the fact that there's a study also suggests a correlation/causation flaw, which is backed up by the conclusion being causal. Are the premises correlations? They sure are. The initial study notes that pravastatin both lowers cholesterol and lowers risk of heart disease, but it doesn't establish that the pravastatin lowers that risk by lowering cholesterol. The other studies similarly show a correlation between cholesterol levels and heart disease, not a causal relationship. As such, this argument jumps from correlative premises to a causal conclusion, and we should look for an answer pointing that out.

Answer Explanation:
This answer highlights the correlation/causation jump in the argument, so it's correct. While pravastatin is associated with lowered risk of (fatal) heart disease, and it does lower cholesterol, it's established only that the lowered cholesterol is correlated with the lowered risk of heart disease. It's possible that pravastatin protects against heart disease through a mechanism other than its effect on cholesterol.

Key Takeaway:
Studies tend to present correlations, so they very frequently are used in arguments that have correlation/causation flaws.

Incorrect. Past scientific findings can still be relevant, and mixing old and new findings to reach conclusions isn't inherently flawed.

Incorrect. Unless the argument specifically sets out a goal to reach a conclusion on a specific topic, it's not flawed to fail to reach a conclusion on a certain topic. Both sets of studies implicate cholesterol in heart disease, and so it's perfectly fine to ignore a potential conclusion about pravastatin in favor of a conclusion about cholesterol.

Incorrect. The percentage of the general population doesn't matter to whether pravastatin has this given effect via its lowering of cholesterol, as it can work if only 1% of the population is on the drug or 50% of the people are.