On October 13, 2012, one of the major sports books in Las Vegas said that there was a 108.8% chance of one of the four teams left in the baseball postseason would win the World Series. Of course it didn’t actually say there was a 108.8% chance of this happening, but the odds that they released to bettors did and helped ensure that over the long run, Vegas wins and we, as a whole, lose.

If you haven’t already, check out Part 1 for a review of AND vs OR probability. Now let’s imagine that instead of betting on outcomes, like we did in the previous article, you’ve wised up and decided to open your own sports book, gMATH. You decide to start simple and offer bettors a chance to bet on which number, 1-4, randomly rolls out of a bingo cage. You realize that the probability of each number being selected is 25%, but you need a way to translate this for paying bettors. In a scenario where four different people each put down $1 on each of the four numbers, one person would win $3 ($4 total – $1 they bet). So you place the very first odds at gMATH’s number guessing game at 3 to 1.

In the long run, gMATH’s inaugural betting event may attract a clientele of people who enjoy watching ping pong balls with painted numbers roll around, but it won’t be bringing you the fortunes that you passed up on business school for. You realize that you need a new betting game that will attract more than just the bingo-loving crowd, involves a small amount of luck, and allow you to make a profit no matter which team wins. As there are exactly four teams left in the postseason, you decide that baseball would make a perfect switch.
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Here are the free GMAT events we’re holding this week. All times listed are local unless otherwise specified.

10/29/12 – Arlington, VA – Free Trial Class – 6:30-9:30 PM

10/29/12 – Dallas, TX – Free Trial Class – 6:30-9:30 PM

10/29/12 – Online – Free Trial Class – 8:00-11:00 PM

10/29/12 – Online – Interview Workshop presented by mbaMission – 8:00-9:30 PM

10/30/12 – Boston, MA – Free Trial Class – 6:30-9:30 PM

10/30/12 – Irvine, CA – Free Trial Class – 6:30-9:30 PM

10/30/12 – Online – MBA Admission Myths Destroyed presented by mbaMission – 9:00-10:30 PM

11/1/12 – New York, NY – GMAT Preview – 6:30-8:30 PM

11/1/12 – Washington, D.C. – Free Trial Class – 6:30-9:30 PM

11/4/12 – Chicago, IL – Free Trial Class – 5:30-8:30 PM

11/4/12 – Online – Free Trial Class – 9:00 AM – 12:00 PM

Looking for more free events? Check out our Free Events Listings Page.

I’ve got a fascinating little GMATPrep problem for you today. Try it out (1 minute 15 seconds) and then we’ll talk about it!

*  As the honeybee’s stinger is heavily barbed, staying where it is inserted, this results in the act of stinging causing the bee to sustain a fatal injury.

 

(A) As the honeybee’s stinger is heavily barbed, staying where it is inserted, this results in the act of stinging causing

(B) As the heavily barbed stinger of the honeybee stays where it is inserted, with the result that the act of stinging causes

(C) The honeybee’s stinger, heavily barbed and staying where it is inserted, results in the fact that the act of stinging causes

(D) The heavily barbed stinger of the honeybee stays where it is inserted, and results in the act of stinging causing

(E) The honeybee’s stinger is heavily barbed and stays where it is inserted, with the result that the act of stinging causes

I chose this problem because it addresses multiple tricky issues that are perhaps easy to hear “ if you have built a good GMAT ear “ but are difficult to explain or articulate. Anything that’s difficult to explain or articulate to yourself is harder to remember. It’s also easier for us to be fooled by our ears on such sentences.

Okay, let’s talk about the problem. My first reaction to the original sentence was: nope, that’s definitely wrong. Now, when the clock is actually ticking and I’m that confident, I don’t bother to try to explain to myself why, exactly, this one is wrong. I just cross off A and look for others that I can cross off for the same reasons I crossed off A.

Here, though, I hit a snag. When I went to the cross off anything else with the same mistake step there wasn’t a single word or location in the sentence on which I could concentrate.
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As we discussed a few months ago, most schools are still determining how to use IR during the admissions process. A recent US News article reports on a new survey just released by Kaplan; the survey lends broader support to the anecdotal reports that we’ve been hearing from individual schools.

Kaplan surveyed 265 business schools, including 17 of the top 25, to find out how they’ve been using IR so far. A little over half are still figuring out what to do with the score, while roughly ¼ of the respondents indicated that they already consider IR important. Even in that last category, though, the schools are still determining how much emphasis to place on IR. US News spoke with Dawna Clarke, Director of Admissions at Dartmouth’s Tuck School of Business and while she does consider IR important, she also indicated that they’re still figuring out exactly how to use the scores in the absence of well-established historical data. In a nutshell: people aren’t quite sure yet what the data means or how much of an impact it should have on admissions.

Expect all of this to begin changing next year. Assuming that the data eventually establishes that the IR section does actually identify strong business school candidates, the schools will likely begin using IR more seriously during the 2013 admissions season (for those who are hoping to enter a program beginning in 2014). How heavily will IR weigh in the admissions decision? We won’t know that until we start to have better analyses of how useful the score is; if it turns out to be a strong predictor of b-school success, then IR is rapidly going to become a very important part of the GMAT.

Remember those times when you were sure you got the answer right, only to find out that you got it wrong? For a moment, you even think that there must be a mistake in the answer key. Then, you take a look at the problem again, you check your work, and you say, I can’t believe I did that! You knew exactly how to do this problem and you should have gotten it right, but you made a careless mistake.

What’s a Careless Error?

By definition, a careless mistake occurs when we did actually know all of the necessary info and we did actually possess all of the necessary skills, but we made a mistake anyway. We all make careless mistakes (yes, even the experts!); over 3.5 hours, it’s not reasonable to assume that we can completely avoid making careless mistakes. Our goal is to learn how to minimize careless mistakes as much as possible.

How Can We Minimize Careless Errors?

Isn’t the whole point of a careless error that we don’t know when we’re going to make them? They just happen randomly and we can’t control that!
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Find the Assumption questions are very common Critical Reasoning question types. If you don’t yet know the general process for tackling Critical Reasoning problems, learn how before you keep reading this article.

Ready to try a question? Set your timer for 2 minutes and try this GMATPrep problem:

In a study conducted in Canada, servers in various restaurants wrote Thank you on randomly selected bills before presenting the bills to their customers. Tips on these bills were an average of three percentage points higher than tips on bills without the message. Therefore, if servers in Canada regularly wrote Thank you on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been.

Which of the following is an assumption on which the argument relies?

(A) The Thank you messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant.

(B) Regularly seeing Thank you written on their bills would not lead restaurant patrons to revert to their earlier tipping habits.

(C) The written Thank you reminds restaurant patrons that tips constitute a significant part of the income of many food servers.

(D) The rate at which people tip food servers in Canada does not vary with how expensive a restaurant is.

(E) Virtually all patrons of the Canadian restaurants in the study who were given a bill with Thank you written on it left a larger tip than they otherwise would have.

Got your answer? Let’s start going through this one!

Step 1: Identify the Question

The question stem contains the word assumption, which is a pretty good clue that this is a Find the Assumption (FA) question. This question type always contains a conclusion and I know it’s important to find that conclusion. Also, if I can, I’m going to brainstorm any assumptions I can think of without taking too much time.
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Here are the free GMAT events we’re holding this week. All times listed are local unless otherwise specified.

10/22/12 – Atlanta, GA – Free Trial Class – 6:30-9:30 PM

10/22/12 – Washington, D.C. – Free Trial Class – 6:30-9:30 PM

10/22/12 – Online – Free Online GMAT Preview – 9:00-10:30 PM EDT

10/23/12 – Online – Long Term Planning Workshop (presented by mbaMission) – 9:00-10:30 PM EDT

10/24/12 – New York (Wall St), NY – Free Trial Class – 6:30-9:30 PM

10/24/12 – Philadelphia, PA – Free Trial Class – 6:30-9:30 PM

10/24/12 – Online – Free Trial Class – 9:00 PM – 12:00 AM EDT

10/25/12 – San Francisco, CA – Free Trial Class – 6:30-9:30 PM

10/25/12 – Online – Thursdays with Ron Review Session – 7:00-8:30 PM EDT

10/27/12 – Boston, MA – Free Trial Class – 2:00-5:00 PM

10/27/12 – Santa Monica, CA – Free Trial Class – 2:00-5:00 PM

10/28/12 – Santa Clara, CA – Free Trial Class – 2:00-5:00 PM

10/28/12 – Online – Free Trial Class – 5:00 – 8:00 PM

Looking for more free events? Check out our Free Events Listings Page.

I had a student write me an e-mail earlier this year complaining about a lack of improvement on his last few practice tests. On three consecutive tests, he scored a 580, 560, & 580. Frustrating for him. But when I looked at the dates of those tests, I wasn’t surprised by his lack of improvement” he had taken the tests on three consecutive days. If students were able to improve by doing as many test questions as they could possibly find, then every student would do better on the verbal section than on the quant section because he or she has already spent  two and a half hours studying before the verbal section begins.

Tests are not good learning tools. Tests are good for assessing what you would likely score on a real GMAT if you took the test with similar problem solving abilities and timing strategies.

This doesn’t mean that tests aren’t important for improving your GMAT score. I’d argue that they are the single most important tool that everyone (yes, everyone) can use to (eventually) improve his or her GMAT score. But think back to the last practice GMAT that you took: by the time that you finished a two and a half hour test that included 78 quant and verbal questions, how many questions did you remember? Probably not a lot.

When that student scored a 580 on his first practice test, he wasn’t satisfied with his score, but he didn’t do anything differently the next time he sat down and took another test. If insanity is doing the same thing over and expecting different results, then the GMAT was making this student insane. So I pointed out two areas for improvement that every student can look for after finishing a practice test: timing and weaknesses. Let’s take a look at one such practice test to see how you might be able to improve your overall GMAT score:
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Are you ready for a challenge? Try to solve the following question in under two minutes:

How many different positive divisors does the number 147,000 have?

If you feel like two minutes are not nearly enough to solve the problem, you’re not alone. Even the most seasoned GMAT veterans might find the problem challenging, as it requires a deep level of understanding of two mathematical concepts: Divisibility and Combinatorics (just a fancy word for ˜counting’).

If I replaced the number 147,000 with the number 24, many more people would be able to come up with an answer:

You could just pair up the divisors (factors) and count them. Start with the extremes (1×24) and work your way in:

1×24

2×12

3×8

4×6

A quick count will show the number 24 has exactly 8 different positive divisors.

The number 147,000 will have many more positive divisors “ too many to count This is a strong indication that we will need to use combinatorics.

Divisibility: Any positive integer in the universe can be expressed as the product of prime numbers.
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Recently, a new student asked me what he could do to get the most out of our class and his study time over the next several months. He’s not the first person to ask me this, but when I was responding to him, I realized that I really needed to write this down and share it with all of you. Many of you have heard me say these things in various forms in articles, blog posts, or forum responses over the years—but here they are in one place.

So, without further ado, the 2 biggest mistakes that people make when studying for the GMAT:

#1 Doing instead of Analyzing

Most people try to study for the GMAT in the same way they studied for school—and, for most people, that isn’t going to lead to a 700+. The GMAT is not a math test or a grammar test—really, it isn’t! It’s a reasoning test—and I’m not just referring to critical reasoning. The GMAT is really a test of how we think. If that’s not your primary focus when studying, you won’t get the best score you could get.
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