powerscore conditional reasoning diagramming for LR section

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powerscore conditional reasoning diagramming for LR section

Postby avacado » Fri Nov 12, 2010 10:44 pm

Does anyone else suck at this? They keep saying you will get over the hump and initially it may be slow- but it will pay off but does it??! No hump in sight here.. I keep trying the powercore method because if I don't know any other way. Is there any other way!??

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Re: powerscore conditional reasoning diagramming for LR section

Postby minnbills » Sat Nov 13, 2010 12:23 am

I took a formal logic course so I think I can help you out a bit. I'm not quite sure exactly what you want to know, so I'll try and lay it out as best I can.

Conditional reasoning is really pretty simple.

If A, then B.

or diagrammed as:

A ---> B

A is the sufficient condition, and B is the necessary condition. The first variable is always the sufficient, the second is always necessary.

If Sufficient

Then Necessary.

A cannot occur without B also occuring.

B can occur without A occuring.

Here's an example:

If I get drunk tomorrow, I will regret my actions.
If A then B.

So, If the sufficient condition (getting drunk) happens, I must also regret my decision. However, I could theoretically regret my actions for an entirely different reason. Thus, B (regretting my actions) could occur without A also occuring.

After reading a stimulus where you think you may have to diagram, make sure you read the question first. With 'what is the conclusion' questions, you basically just have to find a paraphrase/contrapostive of the conclusion already provided, and diagramming is then unnecessary.

Where you do have to diagram, do the following:

1. Use variables. Substitute a few letters for a given idea. For example: "People will make poor economic choices" could be diaggramed as PEC or whatever.
2. Keep these ideas straight. Often the testmakers will use the same basic idea, but phrase it in a way that someone might create two seperate variables, thus throwing off their diagram.
3. ALWAYS DO THE CONTRAPOSITIVE! This cannot be stressed enough. Most of the time, the contrapositive will in some way lead you to the right answer, especially on 'what must be true questions.'

A contrapositive is simply the conditional statement, negated and flipped.

If A then B.
If not B then not A.

Or, as diagrammed in formal logic:

A --->B
~B ----> ~A

All this means is that if B does not occur, then A could not have occured. Because if A occured, B must have occured. I hope this makes sense because understanding how contrapositives work can be really insightful to understanding the nature of conditional reasoning.

When diagramming, you'll often have a 'chain' like this:

Premise: A ---> B
Premise: B ---->C

Conclusion: D ---> E

A question may ask, 'what, if added, would allow the conclusion to be properly drawn?'

Obviously, C--->D is the missing link, and whichever answer choice fills that will be correct. These questions seem simple enough, so the testmakers will often use the contraposive in lieu of the obvious answer to make things more difficult. So, imagine you're looking through the answer choices and nothing seems right. You might see ~D ----> ~C and that would be the right answer. But in sentence form, it might say something like: If people negative results are not being had, then people are studying. Basically, they will hide the contrapositive behind rather awkward language that is easy to write off. But if you diagram it right, then flip and negate, you get this C ---> D which fits prefectly.

I'll stop here because again I'm not sure exactly what kind of help you need. I hope this was hlepful.

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Re: powerscore conditional reasoning diagramming for LR section

Postby paulshortys10 » Sat Nov 13, 2010 1:03 am

I don't know if helped him,but u helped me for sure....thanks ..any advice on justify vs assumption questions?

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Re: powerscore conditional reasoning diagramming for LR section

Postby avacado » Sat Nov 13, 2010 1:25 am

Thank you for taking the time to write out such a great reply!! For me the reasoning is not so much the issue as is the application to a question. Since the wording is different everytime, it takes me forever to understand the stimulus and then whenever I diagram it takes me sooo long to figure out which phrase is equivalent in meaning to which.. and by the time i figure that out reading the choices and deciding which is not compatible reasoning (or vv)--- i am so slow. Please tell me this gets better with practice. I think maybe I am just a little disheartened bc i got a lot of questions wrong back to back and even when i went over the explanations i didn't understand it... :cry: :cry:

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Re: powerscore conditional reasoning diagramming for LR section

Postby AverageTutoring » Sat Nov 13, 2010 9:57 am

Powerscore puts a lot of emphasis on diagramming LR because diagrams are simply an extension of what is going through your head, and the faster you can process that, the faster you can process the question. Do not confuse this with them wanting you to actually diagram every question on the real exam! Only select questions need actually be diagrammed, but the point of diagramming everything to the extreme early on is to force it to become an intuitive process.

Do you actually need to do this? Well, that depends. Are you having trouble with these questions in either accuracy or speed to begin with? If so, then diagramming would be a good route. But if you're already acing them in 20 seconds flat than the diagramming of everything is probably not needed.

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