PrepTest 104, Section 1, Question 2
Although 90 percent of the population believes itself(53 more words not shown)
The argument's reasoning is questionable(7 more words not shown)
- Athose people who(14 more words not shown)
- Bmore than 20(23 more words not shown)
- Cone's being able(17 more words not shown)
- Dan understanding of(19 more words not shown)
- Esince 90 percent(24 more words not shown)
Reading the argument
Do you need to understand DNA to make a good health-care decision?
Someone might understand useful information about nutrition, exercise, or a particular treatment without being able to follow a news story about DNA. A knowledge gap in one subject doesn't automatically mean the person lacks the information needed for every decision in the broader field.
The argument tells us that only 20 percent understand enough DNA for the news story, so the other 80 percent do not. That arithmetic is fine. The questionable step is what the author does with that 80 percent: declaring them unable to make well-informed personal choices or good health-care policy decisions.
What we’re looking for
For the flaw question, I want the missing connection. The author needs to show that understanding DNA is required for those decisions. Otherwise, the survey has identified a gap in DNA knowledge without establishing the much broader inability claimed in the conclusion.
Working the answers
- A
This concerns the 20 percent who do understand DNA. It says that their understanding enables good personal choices. But the conclusion concerns the other 80 percent, who lack that understanding. Even if knowing DNA were one way to be equipped for good decisions, there might be other ways. We need to know why people without it cannot make those decisions.
- B
The argument is about how many individuals lack the relevant knowledge. It does not conclude that society as a whole will be unable to make good policy. A small group could make policy decisions on everyone else's behalf. Whether more than 20 percent need to be informed for that collective result is a different question.
- C
Personal medical choices and public policy decisions are two outcomes the author groups together. The argument doesn't reason from someone's ability to make the first kind of decision to a guarantee that the person will make the second. The unsupported move begins with DNA knowledge, not with personal decision-making ability.
- DCorrect
“Essential” means required. If understanding DNA were required to make either kind of well-informed decision, the 80 percent who lack that understanding would be missing something they need. But that requirement is exactly what the argument never establishes. Knowing how many people cannot follow a DNA story doesn't establish it for us.
- E
We can't establish that at least 70 percent are mistaken about their health-care knowledge merely by comparing 90 percent with 20 percent. The two figures measure different things: confidence about health care and knowledge of DNA. They would expose the claimed mistake only with an additional connection between those subjects. E describes another conclusion that would need support; D identifies the missing requirement behind the argument's actual conclusion.
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