QR - Impossible Qs

[Irrizistuble]

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What are some of the most impossible questions you guys see on the QR section?

In my studying, I think I'm just going to start skipping the probability, P!, nPr type. I can NEVER figure out how to setup those probs!! Does anyone know if Kaplan or some website out there can help with that?

 

[alanan84]

For my statistics class we used Elementary Statistcs by Bluman and it explained all that pretty well. It's also one of the reference books for the QR section of the DAT. You could look into getting it if you need to. I can guarantee you'll see some probability questions in there.

 

[mmorris86]

http://www.analyzemath.com/statistics.html

Under counting do the first two, and under probability do the first two... there are lots of free resources on the internet. Before you consider buying a book or something, spend a few minutes searching the web. This website took me 2 minutes to find by googling "elementary statistics"

 

[tsitneD]

No i recommend that you master these kind of problems then you ll be quick at them and save bunch of time on real dat. On the test there will be some other question that ll be really time consuming. If you know the basics really good you ll fine.

Suppose it two events are asked together for eg. A and B then you multiply AB.

If events are asked such as A or B then you add A+B.

ways to set people around circular table (n-1)!


So try to know the basics and you ll be able to atleast answer few probability question. Trust me it helped me b/c i am horrible at quick math. On the test day you can do these kind of problems and save time for hard word problems. Keep doing these kind of problems you ll get good at them. If you want start from SAT level.

 

[mmorris86]

If events are asked such as A or B then you add A+B.

If you want start from SAT level.

If asked A or B and the events are mutually exclusive, meaning the outcome of one has no effect on the outcome of the other, such as choosing 1 science book out of 5 or 1 math book out of 4. The outcome of which science book you choose has no effect on which math book you choose because they are out of different groups thus you use A + B: 1/5 + 1/4 = 4/20 + 5/20 = 9/20

Now if asked A or B and the events are somehow linked, like choosing cards out of the same deck, you have to use A + B - AB. Check it out: If asked what the probability of choosing a heart or a 9 is out of a deck of 52 cards: 13/52 hearts, 4/52 9's so the chance of getting A or B (heart or 9) is 13/52 + 4/52 - 1/52(chance of getting a 9 of hearts) = 16/52 or 4/13

If you want, start from GRE level.. not SAT, for FREE:

http://www.ets.org/Media/Tests/GRE/pdf/GREmathPractice.pdf

http://www.testprepreview.com/gre_practice.htm

On the testprepreview website, there is also DAT review and practice problems and GMAT for math...