- Tue Jan 20, 2009 12:00 am
#73663
Complete Question Explanation
Weaken. The correct answer choice is (C).
The argument compares two groups of people, those who received treatment from a psychologist for 6 months or less and those whose treatment lasted for a longer period, and showed us that in the latter group a higher percentage of patients felt that the treatment made things a lot better. From this data, the author concludes that treatment for longer than 6 months is more effective than shorter treatment.
As we are asked to weaken the argument, we should be looking for a problem with it, and since it is based primarily on comparing percentages in two different groups we should seek to show that there is something different about those two groups that might have skewed the data in some way. We could look at it causally, for example, and seek out an alternate cause for the higher percentage in the second group, other than the treatment being more effective. Anything that attacks the value of the percentages given to us should do the job of undermining our confidence in the conclusion.
Answer choice (A): Without knowing more, particularly about the percentage in the other group that felt that it made things worse, this answer does no harm to the original claim. Perhaps 70% of the other group felt that way, which would actually strengthen the argument.
Answer choice (B): A difference in response rates certainly can mess up the data in a study, but only if it suggests that the group that responded was too small or was otherwise not representative of the whole group. This answer doesn't go far enough towards showing that one or the other group was not properly represented, and so it does very little, if anything, to weaken the argument.
Answer choice (C): This is the correct answer choice. This answer gives us a key difference between the two groups! If the group that stayed in treatment longer did so in part because they felt it was going well, then of course that group will have a higher percentage of people saying that it helped. It might not actually be helping more - it's just that the people in that group are more likely than those in the other group to feel that way. This means that the second group was not a good representation of all people who enter into therapy, which hurts the data and weakens the argument based on that data.
Answer choice (D): While this indicates that both groups are likely not representative of all patients in each group, it does so in a way that actually strengthens the argument. If dissatisfied people are more likely to respond, and the second group had a higher percentage of satisfied patients in it, that might suggest that longer therapy actually does work better. Their percentage of dissatisfied patients was lower, after all!
Answer choice (E): It is irrelevant what psychologists do or do not suggest to their patients. What matters is what actually works, and whether the survey results accurately reflect that or not. In any event, if we were to trust the expertise of these psychologists, answer E might strengthen the claim that longer therapy is more effective. It certainly does nothing to weaken that claim.
Weaken. The correct answer choice is (C).
The argument compares two groups of people, those who received treatment from a psychologist for 6 months or less and those whose treatment lasted for a longer period, and showed us that in the latter group a higher percentage of patients felt that the treatment made things a lot better. From this data, the author concludes that treatment for longer than 6 months is more effective than shorter treatment.
As we are asked to weaken the argument, we should be looking for a problem with it, and since it is based primarily on comparing percentages in two different groups we should seek to show that there is something different about those two groups that might have skewed the data in some way. We could look at it causally, for example, and seek out an alternate cause for the higher percentage in the second group, other than the treatment being more effective. Anything that attacks the value of the percentages given to us should do the job of undermining our confidence in the conclusion.
Answer choice (A): Without knowing more, particularly about the percentage in the other group that felt that it made things worse, this answer does no harm to the original claim. Perhaps 70% of the other group felt that way, which would actually strengthen the argument.
Answer choice (B): A difference in response rates certainly can mess up the data in a study, but only if it suggests that the group that responded was too small or was otherwise not representative of the whole group. This answer doesn't go far enough towards showing that one or the other group was not properly represented, and so it does very little, if anything, to weaken the argument.
Answer choice (C): This is the correct answer choice. This answer gives us a key difference between the two groups! If the group that stayed in treatment longer did so in part because they felt it was going well, then of course that group will have a higher percentage of people saying that it helped. It might not actually be helping more - it's just that the people in that group are more likely than those in the other group to feel that way. This means that the second group was not a good representation of all people who enter into therapy, which hurts the data and weakens the argument based on that data.
Answer choice (D): While this indicates that both groups are likely not representative of all patients in each group, it does so in a way that actually strengthens the argument. If dissatisfied people are more likely to respond, and the second group had a higher percentage of satisfied patients in it, that might suggest that longer therapy actually does work better. Their percentage of dissatisfied patients was lower, after all!
Answer choice (E): It is irrelevant what psychologists do or do not suggest to their patients. What matters is what actually works, and whether the survey results accurately reflect that or not. In any event, if we were to trust the expertise of these psychologists, answer E might strengthen the claim that longer therapy is more effective. It certainly does nothing to weaken that claim.