Rules and Foundation

Question 1

CR: Logical Flaws

A. Unjustified Assumptions - the most general kind of error involving a hole in the argument.

Most common: unspoken and unsupported premises. P hasn’t been proven before drawn conclusions.

Answer 1

1. Assumes shared beliefs - ex: people over 50 don’t party; kids under 16 makes a mess.
2. Draws extreme conclusions: ex: use words such as must, most, best, worst, far more, sharp, certainly, obviously.
3. Assumes skill and/or will: ex: able to retire? kids willingness to eat veggies?
4. Uses vague or altered terms: ex: more than (cell phone talks vs. text) or same amount
5. Assumes signs of a thing: Thing itself ex: not everyone obeys the law - stop sign -> safe to cross.

Question 2

CR: Logical Flaws

B. Causation errors - Specific kinds of unjustified assumptions around causality. (prevalent on GMAT)

Use words such as: lead to, make, force, prevent, protect, increase/decrease, reduce, cause, to ___ (infinitive)

Answer 2

6. Mixed up correlations and causation: 4 possibilities
   (1) x causes Y
   (2) Y causes x
   (3) Z causes X & Y
   (4) it’s accident, do not have all data.
7. Assumes the futures = past
   past result is no guarantee of future outcome.
8. Assumes the best means success
   Ex. helmet, airbags, contraception, maybe best alternatives, not necessarily 100% effective, but cannot conclude is defective.

Question 3

CR: Logical Flaws

C. Comparison errors - flawed or unjustified comparisons between two groups, situations, etc.

Answer 3

9. Has selection bias -
   (1) . unrepresentative sample (experiment worked in A town, doesn’t mean will work for B town.
   (2) . survivor bias
   (3) . ever-changing pool
10. The troubled analogy - it is never good on GMAT.

Question 4

CR: Logical Flaws

D. Math errors - bad or missing numbers

Answer 4

11. Confuses the quantities

Don’t confuse % with actual $.

Question 5

CR: Logical Flaws

E. Communication errors - in a debate, missing the point of the other side.

Answer 5

12. Missing the point

One’s opinion, others didn’t address.

Question 6

For assumption questions, (looking for the gap or hole to support the conclusion) if answers is expressing an opinion such as “should”, usually is wrong.

Answer 6

none

Question 7

To test assumption:

if an assumption is not true, it will destroy the conclusion.

Answer 7

None

Question 8

Strengthen and Weaken questions is to ask for:

• a new piece of information/assumption that makes conclusion to be valid (strengthen) or invalid (weaken)

Answer 8

True.

Question 9

Evidence Family:

• No conclusions. all premises. no assumptions either.
• two main question types: inference and explain discrepancy

Answer 9

Inference - finding an answer that must be true based on available evidence. (hypothesis = conclusion -> infer question).

Question could ask- statement above best support which following assertions. - Note very similar to strengthening question; however, in inference question, the argument (above) is used to support the correct answer (below). On Strengthen questions, the correct answer (below) is used to support the conclusion of the argument (above).

Question 10

Evidence Family

Percentages vs. real numbers

Answer 10

If a question given discuss % of revenues. We can conclude one is more profitable than another. However, we cannot conclude whether the item will continue to be profitable nor the actual dollar amounts generated from each item.

Question 11

Evidence Family

• Avoid use real world inferences
• Avoid project one person/thing to the population
• Avoid similar language from the passage. (Reverse direction or switch terms traps).

Answer 11

True.

Question 12

Evidence Family

• Discrepancy questions: questions stems will usually contain the word “explain” or “resolve”.

Correct answer will resolve the discrepancy, and show there really isn’t any discrepancy at all.

• Common trap answers for explain discrepancies.

Answer 12

1. it will address one of the premises, but it won’t actually resolve the discrepancy between the two premises.
2. reverse logical traps, where the answer choice actually highlights or points out the discrepancy - that is the answer tells us that there is a discrepancy rather than providing new information to show that there really isn’t a discrepancy.

Question 13

Structure-Based Family

• Describe the Role for boldface font.

What are the two possible method.

Answer 13

1. The Primary Method:
   a. identify building blocks (i.e. conclusion, premise, background)
   b. identify the pattern in the answer choices to match the building blocks identified above.
2. Secondary Method:
   a. Identify argument using Fact, Opinion and Conclusion. (much broad categorization).
   b. eliminate answer choices quickly, but involve guessing.

Common trap answers: - tend to be off by just one word at end of the sentence. (i.e. reject vs. establish)

Question 14

Structure-Based Family

• Describe the Argument (similar to Role)

Majority of the questions will offer two competing points of view and ask us, how one person responds to the argument made by the other person.

Answer 14

Answers might involve:
1. alternative evidence that contradicts the first person’s claim.

2. Demonstrate that some evidence used by the first person is invalid or flawed.
3. introduce new piece of information that the first person failed to consider.

The ultimate attack is designed to find fault with the conclusion, but don’t assume that the second person is attacking the conclusion directly.

Question 15

Assumption - Assumptions fill a gap in the argument. It makes the argument stronger

• Find assumption questions

Answer 15

Assumption family questions:
- Find assumption questions - find an assumption that author must believe to be true in order to draw the conclusion.

Question stem can be:

• which of the following is an assumption on which the argument depends?
• the conclusion above would be more properly drawn if it were established that.

Use negate technique when stuck at two answer choices. - ask if the assumption isn’t true, would it weaken the author’s conclusion.

Question 16

Assumption

• Evaluate the argument

DO NOT make additional assumptions.

Answer 16

The correct answer should offer at least two different “paths”, one that would make the argument stronger and one that would make the argument weaker.

Question stem - which of the following questions would be most useful for evaluating the conclusion?
answers usually contains questions and you ask if yes, then strengthen the conclusion, if no, then weakens the conclusion.

Question 17

Strengthen and Weaken

• both questions ask us to find NEW piece of information.

Answer 17

Most common trap answers include the reverse logic trap and the no tie trap.

Question 18

Reason conjunctions also help identify the conclusion, which appears BEFORE these words. Reason words include words such as because, since, and as.

Structure: [conclusion] because [premise].

Example: Jane will be making herself a sandwich soon because she is hungry.

Answer 18

Naturally, this means reason conjunctions can also help us identify the premise, which will appear immediately AFTER these words, as can be seen in the example above.

Question 19

One clue which can help you identify a conclusion is that conclusions are often recommendations made by the argument’s author:

Answer 19

Examples:

1. The company lost money last year. The company SHOULD do so and so. (c)
2. The company lost money last year. It is RECOMMENDED that the company do so and so. (c)

Question 20

One sign by which a premise can be identified is the use of phrases relating to scientific research or the findings of such research, such as “A study conducted in 1999 showed that…”, or “A researcher studying X found that…”

Answer 20

Example:

A RECENT STUDY has found that satisfied employees are more productive (p). Next year, company X plans to invest $20,000 in increasing employee satisfaction in order to increase productivity and therefore sales. (c)

Question 21

An argument’s conclusion may also be identified by words that describe a judgment, an opinion, a prediction, or (of course) a conclusion. Some of the most commonly used words in this group are conclude that, contend that, believe that, hypothesize that, clearly.

Answer 21

Examples:

1. [premise]. The researcher concluded that»_space; [conclusion].
2. It was hypothesized that»_space; [conclusion]. [premise].
3. [premise]. The mayor believes that»_space; [conclusion].
4. Clearly,»_space; [conclusion]. [premise].

Question 22

Not all Critical Reasoning arguments provide a clear-cut clue to identifying the conclusion, such as a conjunction (e.g., therefore), a recommendation (e.g., The company should do so and so) or conclusion words (e.g., The researcher concluded that).

In the following example, we do not have any tangible clue that will help us identify the conclusion:

Example:
Unfair employment conditions in sweatshops abuse employees’ rights. However, if companies are reluctant to employ personnel in such conditions, they will suffer much greater production costs than companies that agree to these conditions.

This does not mean we are helpless and that the conclusion cannot be identified. It simply means that the process of identifying the conclusion relies on common sense rather than spotting certain words (such as conjunctions). In fact, the clues we’ve learned so far are just there to reaffirm what we understand using our logic and common sense.

Answer 22

The first sentence presents factual information, which means it is the premise.

The second sentence presents the author’s prediction about the situation. Although it is presented as a condition that is necessarily true, this is in fact the author’s own consideration of the situation which is based on the premise. Therefore, it is a conclusion.

The bottom line: conclusions can be identified by:

(a) eliminating the factual information, that is, the premise(s); or
(b) noticing words that indicate which part of the argument is a judgment, opinion, or prediction about the implication of the data in the premise(s).

Question 23

(1) Over the past 20 years, Hormone Replacement Therapy has been used to give new life to aging people, primarily by raising their energy levels. (2) However, research indicates that the hormone dosage used in the past had extremely negative health effects. (3) Doctors want to stop using this type of therapy altogether.

The argument’s conclusion appears in which sentence(s)?

Answer 23

One way to find the conclusion is by finding the premise. What is not the premise is the conclusion and vice versa. The first and second sentences present us with facts and data which are usually the premises. Therefore, sentences 1 and 2 cannot be the conclusion.

Another way to find the conclusion is by asking,”what do these facts (the premise) lead to?” Try putting in the conjunction “therefore” in front of the sentences. Where would therefore most fit? The only place in which therefore fits is in front of sentence 3, as the result of hormone replacement therapy (sentence 1) and the research (sentence 2) lead to what the doctors decided. Decisions, actions, and beliefs on the basis of facts usually indicate the conclusion.

Question 24

(1) Citizens in Country X are frequently complaining that lines in government offices are much longer now than they were 15 years ago. (2) No real measure of the length of the lines in government offices in Country X 15 years ago or today exists, (3) but the citizens’ complaints are almost certainly exaggerated, if not altogether unwarranted. (4) The number of government officials in Country X has quadrupled over the past 15 years whereas the number of citizens has only doubled.

The argument’s conclusion is in which sentence or sentence part?

Answer 24

To identify the conclusion in this argument, try to set factual information and opinions apart. The conclusion is an opinion or a judgement based on the factual information.

Sentence part 3 is the author’s judgment, or opinion, on the matter, supported by the data in all the other sentences. Therefore, this portion can be identified as the conclusion.

Question 25

Similarities: Argument 1 - In a study published in 2008, scientists were able to show that a mutation in the gene HERC2, which regulates the expression of the gene OCA2, is partly responsible for blue eyes in humans. The scientists suggested that a genetic test for that specific mutation could predict if a child would have blue eyes. Argument 2 - The venture capital fund analyst has concluded that investing in the submitted web start-up would be profitable because the founder has a profound understanding of the target market and because recent statistics have shown that such insight is a key element in the success of new enterprises.

Answer 25

Both arguments have the following logical structure (ignore the order of appearance): Premise(s): X is one of the factors in determining Y Conclusion: if X is present, Y will definitely be present In the first argument, X is HERC2 and Y is blue eyes. In the second argument, X is market insight and Y is start-up success. This conclusion is flawed because there are clearly other factors besides X that determine Y.

Question 26

The roads connecting two distant cities in the country of Kahuya allow travelers to drive at a speed of 20 miles per hour. If there are no monsoons which render the roads unusable, and if one makes only one half-hour stop every 4 hours, the journey can be made in 5 days. In the argument, the two portions in boldface play which of the following roles? A. The first is a premise; the second is a generality. B. The first is an inference; the second is a conclusion. C. The first is a conclusion; the second is a piece of evidence. D. The first is a condition; the second is a premise limited by the first. E. The first is an opinion, the second is the conclusion which leads to that opinion.

Answer 26

D. Read the argument and break it down using indicative words: Sentence 1 is a premise because it cites a fact. The first boldface portion, or the first third of sentence 2, limits the generality of the statement made at the end of the sentence. In other words, it's a condition. The second third of sentence 2 is another condition. The second boldface portion, or the last third of sentence 2, is another given, a premise, which is conditioned or limited by the first two thirds of the sentence. Sentence contains "if" - It is a condition that must be fulfilled for the premise at the end of the argument to occur.

Question 27

Disease Z is a medical condition which is transmitted by an airborne virus. The Epidemic Control Center of Country X has conducted tests in all the countries in the breakout area of Disease Z and found that COUNTRIES THAT HAD A POPULAR PUBLIC TRANSPORTATION SYSTEM SUFFERED FROM A HIGHER RATE OF INFECTIONS. Therefore, it was determined that countries with advanced mass transit systems are more liable to experience a breakout of Disease Z. However, IT IS ALSO KNOWN THAT ALL OF THESE COUNTRIES HAVE A GOOD HEALTH SYSTEM WHICH IS ABLE TO PREVENT A BREAKOUT BY QUICKLY IDENTIFYING THE FIRST INFECTIONS. In the argument given, the two portions in boldface play which of the following roles? A. The first is a fact providing support for the conclusion presented in the argument; the second is that conclusion. The first is the conclusion of the argument; the second is a point which weighs against that conclusion. B. The first is a general opinion which the argument favors; the second is evidence which supports this opinion. C. The first is a fact which stands in opposition with later evidence; the second is a conclusion that is in line with that later evidence. D. The first is a fact providing support for the conclusion presented in the argument; the second is an additional fact which weighs against that conclusion.

Answer 27

Sentence 1 is a premise because it cites a fact. The first boldface portion, in sentence 2, reports findings (found that) so it's a premise.Sentence 3 begins with the conclusion conjunction Therefore and is a conclusion based on the previous sentence.The last sentence, the second boldface portion, begins with however, an opposition conjunction. It uses the phrase it is also known, indicating it is a premise, contradicting or alleviating data. The first boldface portion provides data that supports the main conclusion presented in the argument - that of the Epidemic Control Center. The second is additional data that weighs against the ECC's conclusion.