#26 - Researcher: The vast majority of a person’s dreams

[vs1988]

I was hoping to get some help/explanation to a logic reasoning problem I encountered on one of my practice exams. Could someone please explain the structure / reasoning behind the right answer to this problem: December 1998 LSAT, section 1 (logic reasoning), # 26.

[Dave Killoran]

Hi VS,

Thanks for the question. The argument in the stimulus is a bit unusual, and doesn't fall into a conventional (or at least categorically identifiable) reasoning form. In those instances where no obviously identifiable reasoning form is present, you should fall back on the various tests we use to eliminate incorrect answers in Parallel questions.

In this case, the Premise Test--using the premise centered around "majority"-- eliminates every answer except (A) and (D) (because (B), (C), and (E) do not have premises based on a "most" or "majority" idea.

(A) and (D) have similar conclusions, so we need to better understand the abstract relationship of the pieces of the argument, and the stimulus would probably best be characterized by the following abstraction: just because something happens a few times doesn't mean you can believe in it since it doesn't happen most of the time. That test eliminates (A) because (A) does not have the "since it doesn't happen most of the time" part, leaving (D) as the correct answer.

Please let me know if that helps. Thanks!

[vs1988]

This is very helpful! Thanks for making this initially confusing problem much more clear.

On a side note, I also want to say thanks for the work you guys do with PowerScore. I signed up for the weekend course, and found that the online student center recordings are superb. I am especially a huge fan of LSAT scenarios one and the Reading Comp recording - RC recording was life-changing, helped tremendously with the RC section, where I used to struggle the most. Thanks again!

[Dave Killoran]

Awesome, I'm so glad we were able to help And the kind comments are very much appreciated!

[est15]

I got this one right but I wanted to make sure I understood why the other answer choices were wrong. Is (E) incorrect because "a significant number" is not the same as "most"? i.e. "a significant number" is basically equivalent to "many"?

Thanks!

[Lucas Moreau]

Hello, est15,

The flaw in answer choice E is less its numerical values (though "significant" may be distinct from "the vast majority", so it's good that you noticed that) and more that it doesn't precisely parallel the logic.

Look at the language - instead of saying it is unreasonable to assume that living near power lines causes cancer, it says it is unreasonable to deny a connection between living near power lines and cancer. That is the opposite of what the question stem says, that it is unreasonable to assume a connection between vivid dreams and real events.

Specific language in these answer choices trips up many unwary test-takers, especially here at the end of the section when you're fatigued and in a hurry. Be sure to read every word!

Hope that helps,
Lucas Moreau

[mcdonom4]

Hello!

I was just wonder what the Premise Test is? I have the PowerScore LR Bible, but I can't seem to find it anywhere.

Thanks!

[Stephanie Oswalt]

Hi Mcdonom!

Thanks for the question!

This is prep test 27, the December 1998 exam. If you're interested in obtaining a copy of this exam, you can purchase it in the LSAC publication "10 More Actual, Official LSAT PrepTests (PT19-28)": https://shop.powerscore.com/?action=pro ... 00O2WRKIA3

Thanks!

Stephanie

[mcdonom4]

Hi Stephanie!

I think you misunderstood my question. I was referring to the Premise Test that Dave Killoran uses in the second response on this feed in order to find the correct answer. Not the particular preptest that this comes from. I'm already using the official preptests.

[Jon Denning]

Hey mcdonom - thanks for the question (and follow up)!

The Premise Test that Dave mentions above is one piece of our overall methodology used to attack Parallel Reasoning questions. We utilize something called the "Elemental Attack," where we describe five different methods/avenues by which you can accurately and efficiently determine which answer choice most closely matches the argument in the stimulus.

At the heart of the Elemental Attack is the idea that you want to find something particularly notable or recognizable in the stimulus, so that you can quickly evaluate answers to see if they have that defining element or not. For instance, let's say the conclusion in the stimulus is really strong, like "So the government will not approve the bill." That should stand out as distinctive. Accordingly, the correct answer must have the same style conclusion, and one of the five pieces of the Elemental Attack is called the Conclusion Test: if the conclusion in the stimulus is notable for some reason (the absolute denial in the example I just gave being one), then move decisively through the five answers' conclusions to see which has/have the same type of conclusion and which don't. If you're lucky this removes four options and you're done! Less lucky and you'll narrow it down to two or three and you can then choose from among them.

Similarly, another of those five considerations is the Premise Test. In it, you're closely analyzing the nature of the premises used in the original argument and comparing them to the premises used in each answer choice (same idea as the Conclusion Test I just described). So maybe you have two premises and they connect in a conditional manner (like a chain), or maybe one is absolute (always) and another is softer (likely), etc. Regardless, if you can pinpoint something, let's call it special, about the premises in the original argument then that gives you a great filter to apply to the answers, removing those that fail to match premise to premise.

You can perform this type of analysis on a number of different elements in the stimulus, from the overall type of argument you see (maybe it's a conditional chain with a contrapositive, or a strong prediction about the future) to a logical error it contains (like a Mistaken Reversal in conditionality) to premise/conclusion features. The key is spotting something that will be easy to recognize as you work through the answers, so that when it's present in the same way you can hang on to that choice and when it's missing you'll spot the absence right away and eliminate that answer from contention

I hope that helps!

Quick edit: I'm not sure which year's edition of the LR Bible you have so I won't try for page numbers, but you'll find the discussion of the Elemental Attack (including the Premise Test) in the Parallel Reasoning chapter!