ravstime wrote:
A recent study of people who had successfully lost weight and implemented regular exercise routines in their twenties found that, by the age of forty, most had gained back the weight, stopped exercising regularly, or both. Surprisingly, among the study's subjects who had hired personal trainers to help them lose weight and exercise in their twenties, an even higher percentage had regained the weight or stopped exercising than among subjects who had not hired such trainers. The researchers concluded not only that remaining on an effective weight management and exercise program is difficult, but also that personal trainers are largely ineffective in helping people to remain on an effective weight management and exercise program.
Which of the following, if true, most weakens the argument in the passage above?
(A) Subjects in the study who had hired personal trainers had, on average, more free time to exercise than did those who had not hired such trainers.
(B) Some people hire personal trainers for sport-specific training or to rehabilitate injuries, rather than to lose weight or implement a regular exercise program.
(C) The average person's metabolism slows significantly between the ages of thirty and forty, making it more difficult for people aged forty or older to avoid weight gain.
(D) Many of the personal trainers hired by the people in the study were also dietitians who helped their clients design meal plans.
(E) Most people who hire personal trainers do so, at least in part, because they lack sufficient motivation to remain on a diet or exercise regimen by themselves.
I selected option C because it targets the cause mentioned in the conclusion..... Can someone explain the correct ans?
(1) Identify the Question Type
The words "weaken" and "if true" in the question stem indicate that this is a Weaken question.
(2) Deconstruct the Argument
The study found that most subjects no longer maintained the weight-reduction and exercise programs they had followed in their twenties. The argument, however, is not primarily concerned with this generally low maintenance rate; it is most concerned with the fact that, surprisingly, the rate was even lower among subjects who had hired personal trainers. Using that discrepancy, the researchers conclude two things: that it is difficult to maintain a weight management and exercise program and that personal trainers are largely ineffective in helping their clients to do so
(3) State the Goal
For weaken questions, we're looking for an answer that makes the conclusion at least a little less likely to be true or valid. It is a fact that subjects who had hired personal trainers had a lower long-term success rate than did those who had not. To weaken the argument, there must be some other reason (besides the general ineffectiveness of trainers) for why the rate was lower among people who had hired trainers.
(4) Work from Wrong to Right
(A) If anything, having more time to exercise should contribute to a higher rate of success in maintaining an exercise program. (Conversely, individuals with less free time should have more difficulty maintaining such a program.) If this statement is true, then the conclusion of the argument becomes more, not less, likely.
(B) The argument considers only those individuals who hired personal trainers for purposes of weight loss or general exercise; the hiring of trainers for other reasons is irrelevant to the discussion.
(C) If this is true, then it supports the first half of the author's conclusion: it is difficult to remain on a weight loss and exercise regimen over time.
(D) If the trainers helped their clients design meal plans in addition to exercise routines, then the result of the study becomes even more surprising – if anything, strengthening the argument, rather than weakening it.
(E) CORRECT. If this statement is true, then there is selection bias among people who choose to hire trainers in the first place: namely, individuals who hire trainers are precisely those who are, all other things equal, less likely to remain on diet or training programs. If that is the case, then this group would naturally be expected to have a lower rate of success in maintaining weight loss or regular exercise – so such a lower rate does not necessarily signal any ineffectiveness on the part of the trainers.