Venn diagram questions

[voodoochild]

Team,
I have been practicing some LSAT problems (LR). However, I tend to miss examples that require us to draw a venn diagram or at least make a mental picture of those questions. For instance, I missed PT16 S3 Q24 and PT29 S4 Q24; PT29 S1 Q18. Can you please let me know some other similar examples? I miss such questions under timed constraints. After mulling over them for a while, I always have an A-ha experience.

For instance, kids wearing brown shirts are more likely to buy a headphone than those who don't wear brown shirts. Kids, whose mother drive Hummer, are more likely to go to public school than those whose mother don't drive Hummer. In answer choices, the LSAT then mixes all different possible combinations of modifiers. Essentially, the LSAT mixes and jumbles all Necessary and Sufficient conditions. Do you know such questions so that I can do focused practice? I seriously need your help


Thanks in advance.

[Dave Killoran]

Hi Voodoo,

We don't use Venn diagrams in answering our questions because it is inefficient and time-consuming--exactly the properties you don't want to encounter during a standardized test So, unfortunately, we can't point you to other Venn examples.

To learn more about our views on Venn diagramming, please see this link in our Free LSAT Help Area: http://www.powerscore.com/lsat/help/venn_limits.cfm

The good news is that the problems you are seeking are what we call Formal Logic, and our LR Training Type books have separate sections devoted to just Formal Logic problems:

http://shopping.powerscore.com/product_ ... e_Training

http://shopping.powerscore.com/product_ ... ng_Vol._II

Thanks!

[voodoochild]

Dave,
Thank you for your detailed response. I think that I have those books, and I have read that chapter. I really like the analysis presented in that chapter. However, I am mainly concerned about the questions that deal with probabilistic situations (more likely, less likely, increasing percentage, decreasing %, etc) -- topics covered in #/% chapters of your book.

It will be really helpful if you could give some tips about them. I also checked the causal reasoning chapter, and the LR book generally uses normal type of notation to diagram "more likely"/"less likely" situation. It's tricky because the arrows don't convey the probabilistic information. hence, I thought of trying Venn Diagrams. I am not sure whether I am on the right track.

I am open to your thoughts and expert opinion.

[Dave Killoran]

Certainly! Since I know you have the LRB, I'd first suggest checking out the #% chapter in that book. There's a lot of good info in there (at least I think so ). For more problems of that type, check out the #% chapters in the two LR Training Type books you already have.

With likelihoods, they can fall under any of the following topics: Conditional Reasoning, Formal Logic, and Numbers and Percentages. Thus, it depends on the context and presentation as to how the topic would be handled. For example, a phase like "more likely" could be diagrammed conditionally:

• If Gutierrez wins the election, it is more likely that taxes will be increased.
  
  GW MLTI

But maybe it's not presented conditionally, in which case you would go a different direction. As with all LSAT statements, you have to consider each case individually and understand the idea within the context of the overall problem. There would be many instances where you wouldn't even need to diagram such a statement; instead just focus on understanding the meaning.

As for Venn, as you can likely see (pun intended!) from our article on Venn diagramming, visually they can be extremely powerful. The problem is, they are ill-suited for use under time-pressure, and with some students they cause certain unwarranted assumptions to be made that can be damaging. We don't think they are anywhere near the optimal approach for a standardized test.

Thanks!