Summarize Argument
Some people conclude that body size influences mating decisions throughout all societies. This conclusion is based on self-reports of university-age students and on analyses of personal ads for dating partners in newspapers.
Identify and Describe Flaw
The argument is based on a sample that might be unrepresentative. The preferences of university-age students and people who resort to personal ads for dating partners are probably not the same as the preferences of most other people in society.
A
concludes that one kind of event causes another kind of event without ruling out the possibility that both kinds of events are the result of a third kind of event
The conclusion does not assert that one event causes another kind of event. The conclusion concerns a feature (body size) that allegedly plays a role in mating decisions. Body size is not an event. Also, the premise doesn’t present a correlation between two events.
B
bases a conclusion on a sample that may be unrepresentative of the population about which the conclusion is drawn
The conclusion, about “all societies,” is based on reports from university-age students and analyses of personal ads in newspapers. There’s no reason to think these students and people who place personal ads are similar in their preferences to people generally in all societies.
C
concludes that an effect has only one cause in the face of evidence that the effect has multiple causes
The evidence does not suggest that there are multiple factors that play a role in mating decisions. The conclusion also does not assert that body size is the only influence on mating decisions.
D
uses a claim that applies only to entire societies to draw a conclusion about individual persons
The conclusion is not about individual persons. And the evidence does not apply to “entire societies.” The evidence concerns reports from university-age students and analyses of personal ads in newspapers.
E
draws a universal conclusion on the basis of a very small number of individual cases
We don’t know that there were only a “very small number” of individual cases. The stimulus doesn’t tell us how many self-reports or personal ads the conclusion is based on.
"Surprising" Phenomenon
How can the government’s efforts to remove counterfeit bills from circulation be extremely successful while counterfeiters are easily passing counterfeit bills to merchants and banks?
Objective
The right answer will explain how successful government removal of counterfeit bills from circulation does not necessarily (and, in this case, largely does not) preclude counterfeiters from passing their bills to merchants and banks.
A
Government information campaigns that teach merchants and bank tellers how to detect counterfeit bills are more effective than ever.
This does the opposite of what we need. If counterfeit detection campaigns are more effective than ever, we would expect it to be more difficult for counterfeiters to pass their bills to banks and merchants.
B
Governments are continually developing new currency designs with features that are difficult for criminals to counterfeit.
This does the opposite of what we need. New and complex currency designs would likely make it harder for counterfeiters to pass their bills off as real, but we know that they’re having an easy time doing so. We want to know how.
C
Counterfeiters are generally unaware that the percentage of fake bills in circulation is the lowest it has ever been.
This doesn’t matter to us. Whether or not counterfeiters are aware of the percentage of fake bills in circulation, they are passing off their bills easily. We want to know how.
D
Government success in removing counterfeit bills from circulation has caused merchants and bank tellers to become lax in checking for counterfeit bills.
This gives an explanation of how counterfeiters are able to pass off their bills while government counterfeit bill removal programs are successful: merchants and bank tellers, calmed by the government’s success, are being less careful with the bills they accept.
E
Governments are spending larger and larger sums of money in their efforts to remove counterfeit bills from circulation.
This doesn’t matter to us. Increased government spending might contribute to the success of the removal project, but we don’t care why the project is successful. That doesn’t help us understand how counterfeiters are easily passing their bills to merchants and banks.
Summarize Argument: Phenomenon-Hypothesis
The author concludes that lack of trust in one’s neighbors leads to committing crimes. This is based on a study which showed a correlation between neighborhoods in which people routinely lock their doors (taken to be evidence of lack of trust) and higher burglary rates.
Identify and Describe Flaw
The author overlooks alternate explanations for the correlation. Perhaps it’s not that lack of trust leads to a higher burglary rate, but rather, a higher burglary rate leads to lack of trust of neighbors. Or perhaps there’s some third factor that causes both a lack of trust and a higher burglary rate.
A
treats something that is merely sufficient to produce a result as if it were necessary to produce that result
The argument isn’t based on conditional reasoning, so there’s no confusion of sufficient and necessary conditions. There’s nothing presented as sufficient to produce lack of trust or sufficient to produce crimes.
B
draws a moral conclusion from evidence that could only support a factual conclusion
The conclusion is not a “moral” conclusion. It doesn’t involve a value judgment or opinion about what’s good or bad. The conclusion is merely a causal claim.
C
bases its conclusion on data that are contradictory
The argument doesn’t contradict itself. The evidence shows a correlation, and the author proposes a causal interpretation of it.
D
asserts in a premise what it is trying to establish in its conclusion
(D) describes circular reasoning. The conclusion asserts cause; the study describes a correlation. The conclusion is therefore not restated in the premise.
E
treats what could be the effect of something as if it were the cause of that thing
People locking their doors could be an effect of higher burglary rates. But the author assumes that it’s causing higher burglary rates. (E) points out the author overlooks an alternate explanation for the correlation.