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Mar
27
2013

# GRE Reading Comp Logic: the Wrong Rabbit Hole

Last year, I wrote a series of entries about the critical reasoning problems that were recently added to the GRE. Since it’s been a while, let’s revisit that question type — and check out another aspect of critical thinking that confounds many of you.

Here’s a type of problem that’s caused no end of consternation to a lot of my students:

Residents of this state are obligated to renew their driver’s license in two circumstances only: if they accumulate six or more points in moving violations, or if they obtain citizenship in another country. Clarice, who is a citizen of only this country, has been involved in only one accident, which added three points to her license. Therefore, Clarice has no reason to renew her driver’s license at this time.

The argument above depends on which of the following assumptions?

I’m not going to show you the answer choices because the essence of this problem needs to be taken care of long before you ever look at a single choice. When I ask my students for the assumption, I invariably hear answers such as the following:

- “The author assumes that Clarice didn’t receive points from sources other than accidents.”

- “The author assumes that Clarice wasn’t already a citizen of some other place.”

- “The author assumes that Clarice didn’t do something else that would make her have to renew her license.”

All of these wrong answers fall for the same trap: thinking in the way that the test makers want you to think. The test makers say, “Hey! Look at these conditions. Clarice didn’t meet any of them. So, there’s no reason for her to renew her license.” And a lot people look at that line of reasoning and say, “Aha! I bet Clarice DID meet one of those conditions, in some sneaky way.” Then they start drumming up clever ways to force poor Clarice to retake her driver’s exam.

This is what I like to call going down the wrong rabbit hole. The test makers show you a rabbit hole, saying basically, “Hey, you! Think about THIS.” And so you think about whatever “this” is, and you think about it really hard, and the problem is that you shouldn’t have even started thinking along those lines in the first place.

Let’s back up a bit.

Consider this argument:

Boris isn’t obligated to exercise. Therefore, there is no reason for Boris to exercise.

There is no law mandating that Boris be kind to his mother. Therefore, he should be a jerk to her.

How do those arguments sound? Terrible, you say?! But why? If I’m not required to do something, doesn’t that mean I have no reason to do it?

Here, again, is the argument about Clarice, but condensed to the essentials:

Clarice isn’t required to renew her driver’s license. Therefore, she has no reason to renew her driver’s license.

It’s tricky to spot the error the first time someone throws you an argument like this, because renewing a driver’s license is boring and lame, so your brain fills in the gap in the argument: “The only reason anyone would ever renew their license was if they had to.” But that’s not necessarily true: that’s an assumption. Maybe Clarice gets a tax credit for renewing her license, or renewing the license will get some of her points taken away, or renewing the license provides some other benefit to something completely unrelated. We don’t know.

Remember this nugget of logical wisdom when you take the GRE: just because a person isn’t required to do something, doesn’t mean that they shouldn’t or they won’t!

Feb
13
2013

# Efficient Scratch-Paper Work

In my last entry, about quick arithmetic tricks, I mentioned that you should never try to do extensive math calculations in your head. This bears further explanation, as it’s counterintuitive to many students. After all, why wouldn’t it save time to do a few steps in your head, instead of writing them down? The short answer is this: Trying to do more than one step mentally, without writing anything down, will end up taking you more time and will lead to more errors.

Think about the last time that you tried to do multiple steps in your head, and the questions that it ended up raising: Did I remember to divide by 2 at the end? Did I end up with x in the denominator, or was it x2? And once those questions start coming, there are only two options: Proceed with the result you got and hope that it’s correct, or backtrack and run through all of the steps again. Do you like either of those routes? Neither do I. If you instead write down the steps as you’re doing them, you’ll not only avoid a lot of calculation errors, but you’ll also have work to refer back to in case you end up with a result that doesn’t match an answer choice.

And while we’re on the subject of time-saving scratch-work, here’s something else to do at the top of your paper on both the quant and verbal sections:

A___________________________________________________________________________________

B___________________________________________________________________________________

C___________________________________________________________________________________

D___________________________________________________________________________________

E___________________________________________________________________________________

Process of elimination is an important part of test-taking success, but it’s not effective to mentally remember which choices you’ve already eliminated, and it’s inefficient to write out the letters “ABCDE(F)” out 80-100 times. Add a new column to this chart each time you need to keep track of which answers you’ve eliminated, and you’ll save precious minutes on each section – as you’ve learned by now (and as my “arithmetic tricks” entry began driving home), it’s the confluence of many small factors that lead to Test Day confidence and success.

What strategies have you been applying in your studies to work through problems and tests smoothly and accurately? Let us know in the comments!

Dec
21
2012

# GRE Verbal: Use the Clues

The #1 mistake you can make on GRE short verbal problems is looking at the choices too soon. When you solve a short verbal problem, whether it’s a text completion or a sentence equivalence, you should figure out what kind of word should go in the blank before you look at the choices.

Think of it this way: the test makers aren’t your friend. They’re not trying to help you out. So they’re not just going to write random wrong answer choices; they’re going to write wrong answers that will influence your thinking. Don’t fall in for that nonsense.

Here’s a relatively easy problem that turns ugly if you look at the choices too soon:

The Leonidas Achievement Award, though ostensibly prestigious, is held in low repute by some scholars who claim that favoritism runs rampant and that the judges are ______.

A) Partisan

B) Incompetent

C) Immoral

D) Stupid

E) Ugly. Like, really, really ugly.

Did you read the choices before solving the problem? You need to break that habit. Focus on the sentence: the judges are [blank], and the only clue you’ve got is that “favoritism runs rampant.” So, you need a word that indicates that the judges are not fairNow look at the choices: even if you don’t know that partisan means “partial to a specific person,” you can confidently pick it because none of the other words mean “unfair.” Easy problem. Ba-da boom, ba-da done.

If you look at the choices first, though, the story is much uglier. You could argue that the role of a judge is to be impartial, so a judge who plays favorites is bad at her job (B, incompetent). You could argue that people trust judges to be objective, and a judge who betrays that trust is a bad person (C, immoral) or foolish for attaining such a noble responsibility and then shirking it (D, stupid). You could even argue that the judges are ugly, like really really ugly (on the inside).

In short, you could argue a lot of things. And as I wrote last year, any time you find yourself arguing with the GRE, you’re wrong. Look at it this way: either you’re wrong, or the person who literally makes a living writing the test — and can probably score double 170′s in her sleep — is wrong. Let your competition waste their time arguing with the GRE; you have an ego to put aside and points to score.

On the verbal section, that means you need to stop being creative and start using the clues the test makers give you. Don’t argue: use. The sentence says the judges were unfair. So the right answer has to mean “unfair.” Ba-da boom. Ba-da done.

Nov
19
2012

# Equivalent Effect in GRE Sentence Equivalence

I consider Sentence Equivalence the tougher of the two “short” question types of the GRE verbal section. That’s because in a Text Completion, all you have to do is pick the right words — but in a Sentence Equivalence, you have to pick the right words and make sure the words you pick have an equivalent effect on the sentence. It’s this “equivalent effect” requirement that can sometimes make SE’s so maddening to students, and the logic behind it is what I’d like to clarify in this entry.

Let’s start, as we often do, with an example problem:

The professor’s delivery was so _______ that no student was happy, and some walked out before the lecture was half over.

A) Soporific

B) Offensive

C) Boring

D) Galvanizing

E) Demoralizing

F) Enlightening

In short verbal problems, find clues in the sentence and try to predict the blank before looking at the choices. Here, you know that “no student was happy” and that some even walked out on the professor. Clearly, then, the professor’s delivery wasn’t very good. However, you can’t predict exactly what it was about the professor’s delivery that made her lecture so bad. There are many ways in which a lecture could displease students, and that’s where this problem gets tricky.

For starters, let’s kick out galvanizing (“energizing”) and enlightening, which are positive words. That leaves soporific, offensive, boring, and demoralizing.

If you’re a long-time reader of this blog, you might remember what soporific means. But let’s suppose you don’t. What can you do about offensiveboring, and demoralizing? You might get frustrated here because those all seem like reasonable words to put into the sentence. Lectures that offend, bore, or cause students to lose hope could all drive students out of the classroom. But those things are all very different. While all of those words produce a reasonable meaning in the sentence, no two of them produce the SAME meaning.

Thus, even if you don’t know what soporific means, you should be able to tell on GRE Test Day that it MUST be one of the correct answers, since no pairing of the other three satisfies the “equivalent effect” requirement. It so happens that soporific means “sleep-inducing,” so the partner word that yields the same effect is choice C, boring. Choices A and C are the winners.

Sometimes the hardest thing about solving a GRE problem is understanding its requirements. If you’re still confused about Sentence Equivalence, ask here!

Sep
27
2012

# GRE Reading Comprehension and Critical Reasoning, Part III: The Perils of Jaywalking

In this entry and in this one, I discussed two patterns of reasoning that can help you unravel tough problems in GRE reading comprehension. Today our logical journey continues with a look at a classic GRE reasoning flaw of a more quantitative bent: confusing numbers with percentages.

Here’s a silly argument that showcases the flaw nicely:

Common wisdom holds that crossing the street at a corner is safer than jaywalking (that is, crossing in the middle). But annual statistics show that many more pedestrians are hit by cars while crossing at a corner than while jaywalking. Hence, our common intuition is wrong: pedestrians who jaywalk are actually safer than those who don’t.

Are you convinced? I sure hope not, because if so you’ve just dramatically decreased your life expectancy. This argument supports a claim about safety — which is a matter of percentages — with evidence that deals in pure numbers. That’s how the GRE makes such a goofy claim sound so good. The spuriousness (vocab word!) of this reasoning comes to light easily with the help of our old friend, picking numbers. Consider:

Number of corner-crossers: 100
Number of injured corner-crossers: 11

Number of jaywalkers: 10
Number of injured jaywalkers: 10

What’s more dangerous? Jaywalking, clearly — 100% of those people got rammed by cars! Yet the number of law-abiding street-crossers who got injured is greater, simply because there are many more of those people to begin with.

Note that not all GRE arguments use numbers and percentages incorrectly — some do it right. But whenever math comes up in a GRE verbal problem, look closely at the author’s logic to make sure its numeric and proportional crossovers aren’t ridiculous.

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