PrepTest 102, Section 3, Question 7
A commonly accepted myth is that left-handed people(39 more words not shown)
The reasoning is flawed because(2 more words not shown)
- Amakes a distinction(10 more words not shown)
- Btakes no account(13 more words not shown)
- Cuses the word(5 more words not shown)
- Dignores the possibility(11 more words not shown)
- Egives wholly irrelevant(12 more words not shown)
Reading the argument
More accidents in total doesn't tell us who is more likely to cause one.
How many people are in each group? If there are many more right-handed people, they could cause more accidents collectively while each person is less likely to cause one. The author needs to account for the sizes of the populations being compared.
Put numbers on it. Suppose a group has 90 right-handed people and 10 left-handed people. Eighteen of the right-handed people each cause an accident, while four of the left-handed people each cause one. The right-handed group causes more accidents: eighteen versus four. But the share causing an accident is smaller: 20 percent versus 40 percent.
What we’re looking for
Those aren't statistics about real people. They're a possible situation showing why the evidence doesn't establish that the belief is a myth. For the flaw question, I'd look for the missing population comparison. We need accidents relative to the number of people, not just an accident total for each group.
Working the answers
- A
Left-handed and right-handed people are different groups. The argument isn't creating a meaningless distinction between two names for the same thing. Its problem is how it uses the groups' accident totals to assess their members' likelihood of causing accidents.
- BCorrect
We need to know how common left-handed people are relative to right-handed people. If the left-handed group is much smaller, fewer total accidents could still represent a higher rate per person. Our example shows exactly that. The author hasn't supplied the group sizes needed to turn the totals into the comparison the conclusion makes.
- C
“Accidents” doesn't change meaning in the argument. We have a claim about proneness to accidents and evidence about household accidents. A narrower setting doesn't by itself create a second meaning of the word. The numerical problem remains even if every accident counted is the same kind of household mishap.
- D
A jointly caused accident could complicate how accidents are counted, but the mere possibility doesn't explain the missing comparison between group sizes. Our example can have every accident caused by exactly one person and still expose the flaw. We don't need shared responsibility to show why a larger group's total fails to settle individual proneness.
- E
The evidence is relevant, just incomplete. Accident totals are part of assessing who causes accidents; we also need to relate them to the population sizes. And the author doesn't simply dismiss the belief by calling it a myth. The author offers the household-accident comparison as a reason. A weak reason isn't the same as no relevant reason at all.
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