Logical reasoning PrepTest 122 · Section 4 · Question 2

Incorrect. If the conclusion stated that the public could take advantage of the benefits of garlic tablets, then this question might be relevant. As the conclusion is about just the relationship between garlic and CV disease, however, this answer is out of scope.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Argument Evaluation

Stimulus Summary:
Study - Patients over 4 months:
Group 1 - Took a garlic tablet, saw a 12% reduction in cholesterol and 17% reduction in triglycerides
Group 2 - Placebo, saw a much smaller reduction in both
Conclusion - Garlic reduces cholesterol/triglyceride levels, reducing risk of CV disease

Answer Anticipation:
This Argument Evaluation question is based on a study, so we should consider the two most common flaws in such an argument—a sampling flaw, and a correlation/causation flaw.

Is there a sampling flaw here? There's no indication that this study had a large, representative, random sample. In fact, there's no indication any of those requirements for a good sample are true. As such, any answer that asks about any of these features would help in analyzing the argument.

Is there a correlation/causation flaw here? The stimulus presents observed data from the study, which will essentially always be a correlation. From that, it concludes that garlic has an effect on health—a causal relationship. So there is a correlation/causation flaw present here, and any answer that asks about that relationship will help in evaluating this argument.

When a study-based argument has both a correlation/causation flaw and a sampling flaw, the correct answer tends to deal with an alternative cause that wasn't controlled for in the study, so let's look for an answer in that area.

Answer Explanation:
This answer would provide information about an alternative cause of the observed data. If the groups had the same diet outside of the garlic pills, then the garlic pills are looking more likely as the cause of the different blood chemical levels. If either group was eating food relevant to blood cholesterol/triglyceride levels, then that would influence the validity. In asking about other potential causes of the different effects on blood chemical levels, this question would help us evaluate it.

Key Takeaway:
Arguments that rely on studies tend to have sampling flaws or correlation/causation flaws. The two overlap in alternative causes, so when both are present, look for answers bringing up or hinting at another factor.

Incorrect. Whether it takes 2 months, 3 days, or 4 months to see the benefits, there were benefits witnessed associated with taking the garlic pills. This information wouldn't help to evaluate the argument because the correlation would still exist at 4 months, and there are no identified factors that might line up better with a shorter timeline.

Incorrect. The argument is about the group's reaction to the garlic pills. Since the argument is statistical in nature, there's always the possibility for outliers. As such, this question doesn't help evaluate the argument—especially since it's about tolerance instead of what effect the pills had.

Incorrect. This answer is completely out of scope—the use of data in an ad doesn't determine how solid that data is.