PrepTest 121, Section 4, Question 25
Therapist: In a recent study, researchers measured how(47 more words not shown)
The therapist's argument is logically(9 more words not shown)
- Atakes for granted(20 more words not shown)
- Bfails to address(16 more words not shown)
- Ctakes for granted(14 more words not shown)
- Dfails to address(19 more words not shown)
- Etakes for granted(21 more words not shown)
Reading the argument
Seventy-five percent of the problems is not seventy-five percent of the people.
Of the 60 conditions studied, about 45 cleared up within 50 weeks. That's encouraging for those conditions. But how common are they? If the 45 are rare and the remaining 15 affect most people, solving most types of problems would leave most people needing more treatment.
Imagine that one of the slower-to-clear conditions affects 80 percent of the people who need therapy. Even if every other condition cleared up quickly, that common condition could prevent most people from being finished within 50 weeks. We don't know whether that is the real distribution. The point is that the study's percentage counts types of problems, while the conclusion counts people.
What we’re looking for
The flaw question asks us to identify that shift. We need to know how the conditions are distributed among people before using success with most conditions to announce that most people need no more than 50 sessions.
Working the answers
- A
An unstudied condition that takes much longer might matter, especially if it is common. But the therapist doesn't need to assume that no such condition exists. A rare condition could require years of treatment while 50 sessions were still enough for most people. A's blanket exclusion is too strong. The more direct problem remains even if these 60 conditions are the only ones: we don't know which ones affect most people.
- BCorrect
Any one of the conditions could affect most people, including a condition among the roughly 15 that did not consistently clear up within 50 weeks. If that slow-to-clear condition is widespread, success with the other 45 won't establish that most people are finished with therapy. B identifies the missing connection between the number of conditions treated successfully and the number of people whose needs are met.
- C
People could have several problems and work on them during the same weekly sessions. The argument doesn't require every person to have exactly one condition. Multiple conditions might raise further questions, but their mere existence doesn't establish the specific assumption C attributes to the therapist.
- D
The evidence concerns weekly behavioral therapy. Other forms of therapy lacking proof of effectiveness don't tell us whether this treatment resolves these conditions within 50 weeks. We need to examine the inference from the study's results, not assume every form of therapy must be established as effective.
- E
The sample need not have the same average number of problems as the entire population for its treatment results to be useful. People entering therapy could have more problems, and several might be treated at once. E focuses on average counts of problems per person. The unanswered question is which conditions affect how many people, especially the conditions that take longer to resolve.
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