PT 55, Section 3, Question 22 – ???

    • April 17, 2016 at 11:04 am #1735
      mgimbel
      Participant

      I have read and re-read this question 10 times and can not see the logic in answer choice A.  Can anyone explain this question/answer, please?

      Thanks,

      Marc

    • April 17, 2016 at 6:13 pm #1736
      LSAT Dan
      Participant

      There’s a mismatch here between the premises and the conclusion – the premises tell us that the people on the low-carb diet lost more weight than the other group; the conclusion tells us that the relationship is between the diet and body fat.  In other words, there’s an assumption being made that a less weight equates to less body fat.

       

      (A) weakens the argument by giving us a reason to think it’s wrong to equate weight with body fat.  If (A) is true, then the fact that the high-carb diet people didn’t lose much weight doesn’t mean that they didn’t lose much body fat.  They could have lost just as much body fat as the other group; it’s just that they retained water, and so the loss of body fat didn’t bring with it a loss of weight.

    • April 18, 2016 at 6:39 am #1737
      mgimbel
      Participant

      Arrgh!  Damn LSAC.

      Thanks, Dan.

      Marc

    • October 23, 2016 at 4:23 am #2801
      Jane
      Participant

      Hi Dan,

      Thank you for the explanation. I understand that the author assumes that weight = body fat, but I’m having trouble with figuring out why (B) wouldn’t weaken the argument, since (B) argues that one can still lose weight, but gain significant amounts of body fat, which, to me, seemed to be attacking both the premise and conclusion. Could you tell me why (B) is incorrect?

    • October 23, 2016 at 2:02 pm #2802
      LSAT Dan
      Participant

      (B) is consistent with what you say, that one can still lose weight but gain significant amounts of body fat, but notice that (B) doesn’t actually say that; (B) says that you can eat a lot of protein and still gain body fat. It’s true that the argument tells us that the high-protein group lost weight, but that’s true *as a group*; it doesn’t suggest that it’s going to work for everyone. I’m always suspicious of the word “many” on strengthen/weaken questions. Here’s another way to look at it:

      You probably think that smoking causes cancer; however, it’s true that “many” people smoke and don’t get cancer, and “many” people get cancer despite never having smoked. Neither of these facts, though, probably weakens your belief very much. Probabilistic arguments can withstand (a lot of) counterexamples. (B), even if true, is incorporated into the passage, i.e.: “Many people who consume large quantities of protein nevertheless gain significant amounts of body fat; despite that, however (we can’t fight the premises), people on a high-protein, low carb diet lost more weight than the people on the low-protein, high carb diet.” The high carb diet doesn’t have to be 100% successful to be the most effective method. (B) is CONSISTENT with reasoning that would hurt the argument, but (A) weakens it more directly.

      Hope this helps; it’s a subtle point that you raised, and I would certainly agree that (B) is a very attractive wrong answer. Some questions are hard or easy based on how good the second-best answer sounds.

    • October 23, 2016 at 5:41 pm #2803
      Jane
      Participant

      Ahh, I see. I understand now. Thank you for the prompt and very thorough answer, Dan! It was extremely helpful.

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