Friday, October 20, 2006

CR Questions 21 - 30

21). When limitations were in effect on nuclear-arms testing, people tended to save more of their money, but when nuclear-arms testing increased, people tended to spend more of their money. The perceived threat of nuclear catastrophe, therefore, decreases the willingness of people to postpone consumption for the sake of saving money.

The argument above assumes that

A). the perceived threat of nuclear catastrophe has increased over the

B). most people supported the development of nuclear arms

C). people's perception of the threat of nuclear catastrophe depends on the amount of nuclear-arms testing being done

D). the people who saved the most money when nuclear-arms testing was limited were the ones who supported such limitations

E). there are more consumer goods available when nuclear-arms testing increases

22). Which of the following best completes the passage below?
People buy prestige when they buy a premium product. They want to be associated with something special. Mass-marketing techniques and price-reduction strategies should not be used because____

A). affluent purchasers currently represent a shrinking portion of the population of all purchasers

B). continued sales depend directly on the maintenance of an aura of exclusivity

C). purchasers of premium products are concerned with the quality as well as with the price of the products

D). expansion of the market niche to include a broader spectrum of consumers will increase profits

E). manufacturing a premium brand is not necessarily more costly than manufacturing a standard brand of the same product

23). A cost-effective solution to the problem of airport congestion is to provide high-speed ground transportation between major cities lying 200 to 500 miles apart. The successful implementation of this plan would cost far less than expanding existing airports and would also reduce the number of airplanes clogging both airports and airways.

Which of the following, if true, could be proponents of the plan above most appropriately cite as a piece of evidence for the soundness of their plan?

A). An effective high-speed ground-transportation system would require major repairs to many highways and mass-transit improvements.

B). One-half of all departing flights in the nation's busiest airport head for a destination in a major city 225 miles away.

C). The majority of travelers departing from rural airports are flying to destinations in cities over 600 miles away.

D). Many new airports are being built in areas that are presently served by high-speed ground-transportation

E). A large proportion of air travelers are vacationers who are taking long-distance flights.

24). If there is an oil-supply disruption resulting in higher international oil prices, domestic oil prices in open-market countries such as the United States will rise as well, whether such countries import all or none of their oil.

If the statement in the passage concerning oil-supply disruptions is true, which of the following policies in an open-market nation is most likely to reduce the long-term economic impact on that nation of sharp and
unexpected increases in international oil prices?

A). Maintaining the quantity of oil imported at constant yearly levels

B). Increasing the number of oil tankers in its fleet

C). Suspending diplomatic relations with major oil-producing nations

D). Decreasing oil consumption through conservation

E). Decreasing domestic production of oil

25). If there is an oil-supply disruption resulting in higher international oil prices, domestic oil prices in open-market countries such as the United States will rise as well, whether such countries import all or none of their oil.

Which of the following conclusions is best supported by the statement in the passage?

A). Domestic producers of oil in open-market countries are excluded from the international oil market when there is a disruption in the international oil supply.

B). International oil-supply disruptions have little, if any, effect on the price of domestic oil as long as an open-market country has domestic supplies capable of meeting domestic demand.

C). The oil market in an open-market country is actually part of the international oil market, even if most of that country's domestic oil is usually sold to consumers within its borders.

D). Open-market countries that export little or none of their oil can maintain stable domestic oil prices even when international oil prices rise sharply.

E). If international oil prices rise, domestic distributors of oil in open-market countries will begin to import more oil than they export.

26). The average normal infant born in the United States weighs between twelve and fourteen pounds at the age of three months. Therefore, if a three-month-old child weighs only ten pounds, its weight gain has been below the United States average.

Which of the following indicates a flaw in the reasoning above?

A). Weight is only one measure of normal infant development.

B). Some three-month-old children weigh as much as seventeen pounds.

C). It is possible for a normal child to weigh ten pounds at birth.

D). The phrase "below average" does not necessarily mean insufficient.

E). Average weight gain is not the same as average weight.

27). Red blood cells in which the malarial-fever parasite resides are eliminated from a person's body after 120 days. Because the parasite cannot travel to a new generation of red blood cells, any fever that

develops in a person more than 120 days after that person has moved to a malaria-free region is not due to the malarial parasite.

Which is the following, if true, most seriously weakens the conclusion above?

A). The fever caused by the malarial parasite may resemble the fever caused by flu viruses.

B). The anopheles mosquito, which is the principal insect carrier of the malarial parasite, has been eradicated in many parts of the world.

C). Many malarial symptoms other than the fever, which can be suppressed with anti-malarial medication, can reappear within 120 days after the medication is discontinued.

D). In some cases, the parasite that causes malarial fever travels to cells of the spleen, which are less frequently eliminated from a person's body than are red blood cells.

E). In any region infested with malaria-carrying mosquitoes, there are individuals who appear to be immune to malaria.

28). Fact 1: Television advertising is becoming less effective: the proportion of brand names promoted on television that viewers of the advertising can recall is slowly decreasing.

Fact 2: Television viewers recall commercials aired first or last in a cluster of consecutive commercials far better than they recall commercials aired somewhere in the middle.

Fact 2 would be most likely to contribute to an explanation of fact 1 if which of the following were also true?

A). The average television viewer currently recalls fewer than half the brand names promoted in commercials he or she saw.

B). The total time allotted to the average cluster of consecutive television commercials is decreasing.

C). The average number of hours per day that people spend watching television is decreasing.

D). The average number of clusters of consecutive commercials per hour of television is increasing.

E). The average number of television commercials in a cluster of consecutive commercials is increasing.

29). The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.

Which of the following, if true, would most seriously weaken the health officials' explanation for the lower incidence of the disease?

A). Many new water-treatment plants have been built in the last five years in the rural county.

B). Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease.

C). Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

D). Because of medical advances this year, far fewer people who contract the intestinal disease will develop severe cases of the disease.

E). The water in the rural county was brought up to the sanitary standards of the water in neighboring counties ten years ago.

30). The price the government pays for standard weapons purchased from military contractors is determined by a pricing method called "historical costing." Historical costing allows contractors to protect their profits by adding a percentage increase, based on the current rate of inflation, to the previous year's contractual price.

Which of the following statements, if true, is the best basis for a criticism of historical costing as an economically sound pricing method for military contracts?

A). The government might continue to pay for past inefficient use of funds.

B). The rate of inflation has varied considerably over the past twenty years.

C). The contractual price will be greatly affected by the cost of materials used for the products.

D). Many taxpayers question the amount of money the government spends on military contracts.

E). The pricing method based on historical costing might not encourage the development of innovative weapons.

Official answers and explanations --

21). On the basis of an observed correlation between arms testing and people’s tendency to save money, the argument concludes that there is a causal connection between a perception of threat and the tendency not to save. That connection cannot be made unless C, linking the perception of threat to the amount of testing being done, is assumed to be true. Therefore, C is the best answer.
The conclusion does not depend on there having been an increase in the perceived threat over time or on how many people supported the development of nuclear arms. Hence, neither of A and B is assumed. The argument does not deal with those who supported arms limitations or with the availability of consumer goods. Thus, D and E are not assumed.

22). The incomplete passage calls for an explanation of why price-reduction and mass-marketing methods should
not be used for premium products. B, which states that sales of these products require that they appear specials,
provides such an explanation. Therefore, B is the best answer. No other choice offers an appropriate explanation. The diminishing proportion of affluent buyers cited in A argues for using price reductions to attract buyers of lesser means. C suggests that purchasers of premium products find reduced prices attractive, and it has not been established that the methods affect quality or perception of quality. D argues for, rather than against, using mass marketing.

E is inappropriate, since there is no indication that manufacturing costs are relevant.

23). The plan proposes that high-speed ground transportation would be a less expensive solution to airport congestion than would airport expansion. B indicates that between the cities to be served by the plan there is substantial air travel to which ground transportation would represent an alternative. Therefore, B is the best answer.

No other choice could be cited appropriately. A and D both provide some evidence against the plan. A by emphasizing the likely costs of providing high-speed ground transportation is not by itself a solution to airport

D by indicating that such an alternative is not by itself a solution to airport congestion.
C and E say that there are many travelers for whom the proposed system would actually provide no alternative.

24). If the statement about oil-supply disruption is true, domestic oil prices in an open-market country will rise when
an oil-supply disruption causes increased international oil prices. A reduction in the amount of oil an open-market country consumes could reduce the economic impact of these increases. D gives a way to reduce oil consumption and is thus the best answer.

A and E describe policies that could actually increase the long-term impact of increases in international oil prices, so neither of these choices is appropriate. No relationship is
established between the economic impact and either the number of oil tankers or diplomatic relations in B and C,
so neither of these choices is appropriate.

25). If the oil market in an open-market country were independent, fluctuations in international oil prices would not affect domestic oil prices. However, if the statement about oil-supply disruption is true, it is evidence that domestic oil prices are dependent on the international market and hence that the domestic oil market is a part of the international oil market. Therefore, C is the best answer.

B and D are not supported, since each contradicts the claim that an international oil-supply disruption will lead to rising oil prices in an open-market nation. Nor are A and E supported, since the statement provides information only about the effect of disruption on oil prices, not domestic producers or distributors.

26). The evidence on which the conclusion is based concerns only average weight, but the conclusion concerns average weight gain. Because there is not necessarily a connection between an absolute measurement-such as weight-and a rate of increase-such as weight gain-this argument is flawed. The relevant reasoning error is described in E, which is the best answer.

Neither of A and D identifies a reasoning error in the passage, since the passage makes no claim that weight is the only relevant measure of infant development in general, and no claim about sufficiency. B and C are consistent with the claims in the passage, and neither identifies a flaw in the argument.

27). The passage concludes that, because the malarial parasite cannot reside in red blood cells for more than 120
days, the malarial parasite cannot cause fever more than 120 days after infection. However, according to D, there is a site in the body where the parasite could reside for more than 120 days after infection. Therefore, D weakens the conclusion and is the best answer.

The resemblance between malarial-fever symptoms and those of other diseases, the existence of other malarial symptoms, and the possibility of immunity to malaria are irrelevant to the issue of the conditions under which malarial fever can occur. B provides confirmation for the existence of malaria-free regions but does not otherwise bear on the conclusion.

28). Because E indicates that the number of commercials in a cluster is increasing, it entails that proportionally more
commercials are aired in intermediate positions. Hence, E helps fact 2 explain fact 1 by showing that increasingly more commercials are aired in positions in which viewers find them difficult to recall. E is the best answer.

A testifies to the ineffectiveness of television advertising but does not help fact 2 explain fact 1.
B indicates that fact 2 contradicts rather than explains fact 1, since it suggests that the number of commercials per cluster is decreasing.
C and D help to explain fact 1-by describing a change in viewing habits and a change in programming-but neither relates fact 2 to fact 1.

29). The health officials’ explanation assumes that the decrease in the number of people diagnosed with the disease
accurately reflects a diminution in cases of the disease. By pointing out that this assumption is false, C undermines the officials’ explanation and thus is the best answer. Since A supports the view that sanitary conditions have been improving, it tends to support the officials’ explanation. B also tends to support the officials’ explanation, because it eliminates a factor that might have differentiated between those contracting and those not contracting the disease and thus rules out an alternative explanation. The reduction of the severity of the diagnosed cases does not bear on the officials’ explanation. So D is not correct. Since the standards in
neighboring counties might themselves have been inadequate, E does not weaken the officials’ explanation.

30). If the original contractual price for the weapons purchased incorporated an inefficient use of funds, then, since historical costing merely adds to the original price, it preserves these inefficiencies. An economically sound pricing method should at least allow the possibility of reductions in price as such inefficiencies are removed. Hence, A is the best answer. Because historical costing responds to inflation, B and C are consistent with the economic soundness of historical costing-the rate of inflation and costs that are reflected in inflation. D offers no grounds for questioning the economic soundness of historical costing in particular. Historical costing applies to standard weapons only, not to the innovative weapons that are mentioned in E.

Monday, October 9, 2006

Critical Reasoning Boldface Questions 1 - 4

1). The survival of the publishing industry depends upon the existence of a public who will buy the printed word in the form of newspapers, books and magazines. Over the past several years, however, the advance of electronic media, particularly CD-ROMs, online computer services, and the Internet, has made 9information available to the public electronically without the need for printed materials. As the availability of electronic media increases and as it is more easily accessible, the public has less need for printed materials. So the publishing industry is threatened by the advance of the computer information age.

The two portions in boldface play which of the following roles?

(A) The first is the part of evidence that the argument includes, the second is the conclusion that can be drawn only from the first.

(B) The first is the second-premise that the argument includes; the second is the conclusion that is reasonably drawn form this passage.

(C) The first is the second-premise that the argument includes, the second is the inference that must be drawn from this argument.

(D) The first is the fact that must be true, the second is the inference that can be correctly drawn from this argument.

(E) The first is the part of premise that the argument depends on; the second is the conclusion that is incorrectly drawn from this argument

2). Gasoline-powered boat engines manufactured in the a North American country prior to 1990 contribute significantly to the pollution found in the world¡¯s oceans. In 1990, however, the government imposed stricter pollution controls on gasoline engines manufactured for boats, and beginning in 1995, the government imposed a program of inspections for pre-1990 boat engines with increasingly rigorous pollution standards. As the older boat engines fail to pass inspection, boat owners are increasingly retiring their old engines in favor of newer, less-polluting boat engines. As a result, the amount of pollution these older boat engines emit into the world's oceans will steadily decrease over the next ten years.

The two portions in boldface play which of the following roles?

(A) The first is a pattern of cause and effect that acts as an evidence in support of this argument; the second is the conclusion that can be drawn from this argument.

(B) The first is a fact that acts as a principle in support of this argument; the second is the conclusion that must be drawn from this argument.

(C) The first is a pattern of cause and effect that acts as an special evidence in support of the conclusion; the second is a general point that can be drawn from this argument.

(D) The first is a pattern of cause and effect that acts as the third evidence in support of the argument; the second is a conclusion that must be true.

(E) The first is a final evidence in support of the argument; the second is a conclusion that can be drawn only from the first.

3). The interstitial nucleus, a sub-region of the brain's hypothalamus, is typically smaller for male cats than for female cats. A neurobiologist performed autopsies on male cats who died from disease X, a disease affecting no more than 0.5 percent of male cats, and found that these male cats had interstitial nuclei that were as large as those generally found in female cats. Thus, the size of the interstitial nucleus determines whether or not male cats can contract disease X, but, the hypothalamus is known not to be causally linked to disease Y, and disease X is a subtype of disease Y.

The two portions in boldface play which of the following roles?

(A) The first is a fact in support of the consideration that is one of two points of this argument; the second is the alternative point that weighs against the first.

(B) The first is an evidence that supports the consideration that the argument includes; the second is the fact that weighs against that consideration that could be drawn from the first.

(C) The first is a general principle that is against the conclusion; the second is that conclusion.

(D) The first is an evidence that supports the conclusion; the second is an exceptional example.

(E) The first is a fact in support of the conclusion that the argument depends on; the second is a fact that is against the first one.

4). To be accepted as a member at the Brown Country Club, one must have a net worth of over ten million dollars and must not have any connections to the entertainment industry. Robert Chase, the publishing magnate, has a net worth of 5 billion dollars and chase has not financed any Hollywood movies, so he must be accepted as a member at the Brown Country Club.

The two portions in boldface play which of the following roles?

(A) The first is the part of evidence in support of this argument; the second is the conclusion that could not be drawn from all evidence that the argument contains.

(B) The first is the first-evidence that supports this argument; the second is the mainpoint that must be drawn from all evidence that the argument includes.

(C) The first is the one fact of two that argument includes; the second is the conclusion that could be drawn from this passage.

(D) The first is the background that is necessary for this argument; the second is the conclusion that is not drawn only from the first.

(E) The first is the cause that the argument includes; the second is the effect that can be drawn only from this cause.

Answers --

1). The correct answer is D.
The first portion of BF is a fact --- Over the past several years …
Evidence --- As the availability of electronic...….. printed materials"Conclusion --- So the publishing industry……. the computer information age

A, B, C, E – incorrect -- the first statement is considered as premise. Further the use of “only” in choice A also makes it incorrect.

2). The correct answer choice is A.
The 1st BF is a premise showing 'cause and effect' relationship --- As the older boat….boat engines
The 2nd BF is the conclusion --- the amount of pollution… en years.Fact --- the government imposed stricter pollution ……
B – incorrect – 1st BF is not a fact. Use of MUST incorrect too.
C – incorrect – 1st BF is not special evidence, and 2nd BF is a conclusion instead of just being a general point.
D – incorrect – use of MUST makes it incorrect as extrem tones are not generally entertained in GMAT. Also the 1st Bf is not the 3rd evidence but is followed from a series of cause and effects sted before.
E – incorrect – the 1st is not the final evidence. Further the use of “only” makes this choice incorrect.

3). The correct answer choice is A.
Conclusion --- "thus the size of interstitial...contract disease X"
B – incorrect -- from the second you cannot draw the first. 2nd statement is combination of two facts. From these two facts you can conclude that -- hypothalamus is not directly related to disease X
So not fact itself but conclusion derived from these facts weighs against that consideration
C – incorrect -- conclusion is "thus the size of interstitial...contract disease X" and not the 2nd.
D – incorrect -- 2nd is general and not exceptional.
E – incorrect -- 1st and 2nd are not contradictory to each other.

4). The correct answer choice is A.
1st BF portion is part of evidence --- Robert Chase, the publishing magnate…. Hollywood movies --- it tells that Chase has more than 10 million dollars, but it also states that Chase has not financed any Hollywood movies. Not financing hollywood movies does not imply that he does not finances any other entertainment businesses too.

2nd BF portion is the conclusion --- he must be accepted ….. Brown Country Club.
There are 2 conditions which must be fulfilled in order to be accepted as a member of Brown Country Club, firstly – should have over 10 million dollars and secondly -- should not have any connections to the entertainment industry -- the two required conditions are not fulfilled, thus the conclusion that cannot be drawn from the evidences stated in the first part.
B – incorrect – use of MUST incorrect.
C – incorrect – the conclusion cannot be drawn from this passage.
D – incorrect – the statement preceding the 1st BF is the background.
E – incorrect – use of “only” makes this choice incorrect.

How to approach Boldface Question in Critical Reasoning !

Firstly BF CR (Bold face Critical reasoning) questions lie in tough category -- so if you come across one - will imply that you are doing extremely well in GMAT

In BF CR argument question, one or two different statements in stimulus appear in BOLD. The question then asks you the way in which the two statements in bold are related?

Few basic terms that form the parts of an argument --

1). Argument

An argument is a conclusion supported by premises and assumptions. It has 3 parts: Conclusion, Premise and Assumption.

2). Conclusion

A conclusion is a claim, the main point of an argument. Certain words are used to introduce the conclusion of an argument, these words are termed as Conclusion Indicators e.g -- so, thus, therefore, as a result, consequently, accordingly, hence,imply, conclude that, follows that, means that, infer that

3). Premises

Premises are parts of argument that support the conclusion.They are the reasons that back up the claim made in the conclusion. Most of the time premises are facts, but they can also be assertions that are just given as evidence for the claim in the conclusion. A conclusion gets support:premises provide it. In simple words a premise is a stated reason, a piece of evidence that supports the conclusion. Premises are the argument's facts.They are the facts or evidence that support or lead to the conclusion.
Certain words are used to introduce the premises of an argument, these words are termed as Premise Indicators. e.g – because, since, for, as, if, assume, suppose, evidence, on the basis of, the reason is that, may be derived from, in that

4). Assumption

An assumption is an unstated premise that supports the conclusion. It is something that the author’s conclusion “depends on” or “relies on”.

5). Inference

We can infer many details from the arguments. Inferences are those details, which are known to be true from information presented. Sometimes there is no difference between a conclusion and an inference. When the conclusion to an argument is not explicitely stated, it is something you can infer. In other words, inferences have nothing to do with the main point of an argument. You can infer inferences from the facts that are stated as premises.

6). Background

Information or circumstances required to put the evidence into context but which, on standing alone as pieces of information, might not constitute an evidence that is necessary to arrive at a conclusion. It doesn't states anything directly, just provides the general information related to the topic...

7). Pre-evidence in almost same as background.. .

8). Evidence

Information indicating whether something is true or valid. It is something that supports the argument, or tries to prove it's validity .
Evidence may include facts, but an evidence is usually stronger than a fact. The evidence are the direct elements required for the conclusion to stand whereas facts are not necessary for the conclusion to stand.

9). Fact

Something that is definitely the case. It is the information used as evidence.

10). Consideration

Something which was taken into account or given careful thought before arriving to the conclusion or while making a decision.

11). Principle

Something that is broad and basic rule or truth / fundamental that is not put to question. A principle can be stronger than a fact because it is not specific to a limited number of cases but instead, apply to a broader range of scenarios(and often deeper in meaning).

12). Counter premise/Evidence

While an author always wants to present a strong case, he may concede minor points that weaken his argument to show that he is open-minded and that his ideas are well-considered.These points are termed as counter premises.
This technique also disarms potential arguments against his position.
Counter-evidence Indicators -- actually, despite, admittedly, except, even though, nonetheless, nevertheless, although, however, In spite of, do, may

How to approach Boldface Question -

1).Read carefully the set of statements on which the question is based.

2). Identify the conclusion. Be alert to clues in the text i.e Conclusion Indicators e.g -- so, thus, therefore, as a result, consequently, accordingly, hence,imply, conclude that, follows that, means that, infer that.

3). Pay attention to the evidence that the author uses to support/ argue against a position.

4). Look out for for various argument indicators to analyse and determine the relationship between evidence and conclusion. e.g Premise indicators, Counter premise indicators, Conclusion indicators etc.

NoteDo not mistake evidence for counter evidence.

Saturday, October 7, 2006

CR Questions 11 - 20

Questions 11-12 are based on the following.

To protect certain fledgling industries, the government of country Z banned imports of the types of products those industries were starting to make. As a direct result, the cost of those products to the buyers, several export-dependent industries in Z, went up, sharply limiting the ability of those industries to compete effectively in their export markets.

11. Which of the following can be most properly inferred from the passage about the products whose importation was banned?

(A) Those products had been cheaper to import than they were to make within country Z’s fledgling industries.

(B) Those products were ones that country Z was hoping to export in its turn, once the fledgling industries matured.

(C) Those products used to be imported from just those countries to which country Z’s exports went.

(D) Those products had become more and more expensive to import, which resulted in a foreign trade deficit just before the ban.

(E) Those products used to be imported in very small quantities, but they were essential to country Z’s economy.

12. Which of the following conclusions about country Z’s adversely affected export-dependent industries is best supported by the passage?

(A) Profit margins in those industries were not high enough to absorb the rise in costs mentioned above.

(B) Those industries had to contend with the fact that other countries banned imports from country Z.

(C) Those industries succeeded in expanding the domestic market for their products.

(D) Steps to offset rising materials costs by decreasing labor costs were taken in those industries.

(E) Those industries started to move into export markets that they had previously judged unprofitable.

13. The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the free-wheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.

Which of the following, if true, most seriously weakens the argument presented above?

(A) Cars, buses, and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.

(B) Cars and buses are not nearly as fast as the high-speed train will be.

(C) Planes are not a free-wheel system because they can fly upon between airports, which are less convenient for consumers than the high speed train’s stations would be.

(D) The high-speed train line cannot use currently underutilized train stations in large cities.

(E) For long trips, most people prefer to fly rather than to take ground level transportation.

14. Correctly measuring the productivity of service workers is complex. Consider, for example, postal workers: they are often said to be more productive if more letters are delivered per postal worker. But is this really true? what if more letters are lost or delayed per worker at the same time that more are delivered?

The objection implied above to the productivity measure described is based on doubts about the truth of which of the following statements?

(A) Postal workers are representative of service workers in general.

(B) The delivery of letters is the primary activity of the postal service.

(C) Productivity should be ascribed to categories of workers, not to individuals.

(D) The quality of services rendered can appropriately be ignored in computing productivity.

(E) The number of letters delivered is relevant to measuring the productivity of postal workers.

15. Male bowerbirds construct elaborately decorated nests, or bowers. Basing their judgment on the fact that different local populations of bowerbirds of the same species build bowers that exhibit different building and decorative styles, researchers have concluded that the bowerbirds’ building styles are a culturally acquired, rather than a genetically transmitted, trait.

Which of the following, if true, would most strengthen the conclusion drawn by the researchers?

(A) There are more common characteristics than there are differences among the bower-building styles of the local bowerbird population that has been studied most extensively

(B) Young male bowerbirds are inept at bower-building and apparently spend years watching their elders before becoming accomplished in the local bower style.

(C) The bowers of one species of bowerbird lack the towers and ornamentation characteristic of the bowers of most other species of bowerbird.

(D) Bowerbirds are found only in New Guinea and Australia, where local populations of the birds apparently seldom have contact with one another.

(E) It is well known that the song dialects of some songbirds are learned rather than transmitted genetically.

16. A greater number of newspapers are sold in Town S than in Town T. Therefore, the citizens of Town S are better informed about major world events than are the citizens of Town T.

Each of the following, if true, weakens the conclusion above EXCEPT:

(A) Town S has a larger population than Town T.

(B) Most citizens of Town T work in Town S and buy their newspapers there.

(C) The average citizen of Town S spends less time reading newspapers than does the average citizen of Town T.

(D) A weekly newspaper restricted to the coverage of local events is published in Town S.

(E) The average newsstand price of newspapers sold in Town S in lower than the average price of newspapers sold in Town T.

17. A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 tree to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora’s extinction.

Which of the following, if true, most seriously weakens the argument above?

(A) The drug made from ibora bark is dispensed to doctors from a central authority.

(B) The drug made from ibora bark is expensive to produce.

(C) The leaves of the ibora are used in a number of medical products.

(D) The ibora can be propagated from cuttings and grown under cultivation.

(E) The ibora generally grows in largely inaccessible places.

18. High levels of fertilizer and pesticides, needed when farmers try to produce high yield of the same crop year after year, pollute water supplies. Experts therefore urge farmers to diversify their crops and to rotate their plantings yearly. To receive governmental price-support benefits for a crop, farmers must have produced that same crop for the past several years.

The statements above, if true, best support which of the following conclusions?

(A) The rules for governmental support of farm prices work against efforts to reduce water pollution.

(B) The only solution to the problem of water pollution from fertilizers and pesticides is to take farmland out of production.

(C) Farmers can continue to make a profit by rotating diverse crops, thus reducing costs for chemicals, but not by planting the same crop each year.

(D) New farming techniques will be developed to make it possible for farmers to reduce the application of fertilizers and pesticides.

(E) Governmental price supports for farm products are set at levels that are not high enough to allow farmers to get out of debt.

19. Shelby Industries manufactures and sells the same gauges as Jones Industries. Employee wages account for forty percent of the cost of manufacturing gauges at both Shelby Industries and Jones Industries. Shelby Industries is seeking a competitive advantage over Jones Industries. Therefore, to promote this end, Shelby Industries should lower employee wages.

Which of the following, if true, would most weaken the argument above?

(A) Because they make a small number of precision instruments, gauge manufacturers cannot receive volume discounts on raw materials.

(B) Lowering wages would reduce the quality of employee work, and this reduced quality would lead to lowered sales.

(C) Jones Industries has taken away twenty percent of Shelby Industries’ business over the last year.

(D) Shelby Industries pays its employees, on average, ten percent more than does Jones Industries.

(E) Many people who work for manufacturing plants live in areas in which the manufacturing plant they work for is the only industry.

20. . Some communities in Florida are populated almost exclusively by retired people and contain few, if any, families with small children. Yet these communities are home to thriving businesses specializing in the rental of furniture for infants and small children.

Which of the following, if true, best reconciles the seeming discrepancy described above?

(A) The businesses specializing in the rental of children’s furniture buy their furniture from distributors outside of Florida.

(B) The few children who do reside in these communities all know each other and often make overnight visits to one another’s houses.

(C) Many residents of these communities who move frequently prefer renting their furniture to buying it outright.

(D) Many residents of these communities must provide for the needs of visiting grandchildren several weeks a year.

(E) Children’s furniture available for rental is of the same quality as that available for sale in the stores.

Official answers and explanation --

11. In Z, when the government banned imports of certain products the cost of those produces rose, so the products
must have been cheaper to import than they were to make in Z. Therefore choice A is the best answer.
None of the other choices can be inferred. Country Z need have had no plan to export those products later (choice B), nor need the products have come previously from those countries to which country Z exported goods (choice C).
The products need not have become more expensive before the ban (choice D), and they could have been imported in relatively large quantities (choice E).

12. When the cost of the products rose, the competitive ability of those export-dependent industries that bought them was sharply limited. This fact strongly supports the claim that those industries did not have sufficiently high profit margins to enable them to absorb the price increase, so choice A is the best answer.
Given the limitation on their competitive ability, it is unlikely that those industries would be able either to expand
their domestic markets (choice C) or to enter into new export markets (choice E).
The other choices relate
situations that would be possible but that are not strongly supported: other countries could have continued to
permit imports from Z (choice B), and the industries may have unable to decrease labor costs (choice D).

13. The author argues that planes, since they are a free-wheel system, will be preferred to the high-speed train.
Choice C weakens the argument by pointing out that planes are not a free-wheel system and are les convenient than the high-speed train would be. Thus C is the best answer.
The special feature of the high-speed train described in A is not one that clearly affects consumer choice one way or the other way. Since it is planes that would compete effectively with the proposed trains, the fact that cars and buses might not do so is irrelevant. Non-availability of certain station (choice D) and the consumer preferences described in choice E tend to make the proposed train less, not more, attractive and so both choices strengthen the argument.

14. The critique of the proposed purely quantitative measure of productivity raises the issue of quality of service, which implies that quality of service is a potentially relevant consideration. Thus, choice D is the best answer.
The objection assumes that postal workers are a suitable illustrative example of service workers in general; thus,
choice A is inappropriate.
By delivery of letters, the argument treats letter delivery as the primary activity of
postal workers; thus, choice B is inappropriate. Because the passage explicitly ascribes productivity to entire
categories of workers, choice C is inappropriate. Choice E is inappropriate, since the objector does not question
the relevance of the number of letters delivered but implies that something else might also be relevant.

15. The information in choice B says that young bowerbirds progress slowly toward mastery of a bower-building
style, which suggests that the skill is one they must learn, rather than one whose transmission is wholly genetic.
Choice B also suggests a means of cultural transmission, namely, observation of older birds’ technique. Thus, B
supports the conclusion and is the best answer.
That differences within building styles are outnumbered by similarities (choice A) and that local populations have
little contact (choice D) are both equally consistent with building-style differences being culturally acquired or
genetically transmitted. Nor are differences among species of bowerbird (choice C) the issue. Finally, choice E
confirms the possibility of birds leaning skills, but it is not evidence that bower-building styles are learned.

16. The conclusion is based on comparing newspaper sales in Town S and Town T. Four answer choices indicate
why greater newspaper sales in S need not imply that citizens of S are better informed about world events.
Choice B suggests that many newspapers sold in S inform citizens of T, not S.
Choices A and C both show how
greater newspaper sales can occur without the average citizen having greater familiarity with the news. Finally,
choice D suggests that much newspaper reading in S is not a source of information about world events. The price differential noted in E might help to explain the difference in sales, but it does not undermine the conclusion based on that difference. Therefore, E is the best answer.

17. If the ibora can be successfully cultivated, it is possible to continue production of the drug without threatening the
ibora with extinction. Therefore, choice D is the best answer.
If production continues, the method for distributing the drug aftr it has been produced (choice A) is not likely, on its own, to have consequences for the continued existence of the ibora. Nor is the price of the drug (choice B). If the leaves of the ibora also have a use (choice C), the threat of extinction is strengthened rather than weakened. Finally, if the ibora is largely inaccessible (choice E), this bears on the question of whether production of the drug could continue, not on what would happen if it did continue.

18. Farmers benefit from governmental price supports only when they produce the same crops from year to year. Farmers who wish to receive the benefit of these price supports will be unlikely to reduce water pollution
because they will not follow the experts’ advice regarding diversification and rotation. Thus, A is the best answer.
Since the experts’ advice is evidently their favored solution, the notion that the sole solution is something else (choice B) is not supported. The statements mention neither farmers' costs and revenues nor development in farming techniques, and thus support no conclusions about prospects for profits (choice C) or future farming techniques (choice D). Because no information is given about either the amount of price support or farmers debt, choice E is not supported.

19. According to choice B, the effect of lowering wages is to reduce quality sufficiently to reduce sales. This is a good reason to doubt that wage cuts would give Shelby Industries any competitive advantage, so choice B is the
best answer.
Some of the other choices provide good reasons for, rather than against, lowering wages. Choice A implies that
reducing the cost of raw materials is not possible, choice D indicates that Shelby Industries’ wages are relatively
high, and choice E suggests that Shelby Industries would not lose many workers if it did reduce wages. Choice
C gives a reason for Shelby Industries to be concerned about its competitive position but no reason to think
wage cuts would not improve that position.

20. If many residents of these communities host visiting grandchildren several weeks a year, as D states, that in
itself might generate sufficient demand for rented children’s furniture to support thriving businesses. Thus, D
helps reconcile the apparent discrepancy and is the best answer.
The few households mentioned in choice B are unlikely to generate sufficient demand for rental businesses to
thrive. Similarly, choices A and E, though they provide information concerning the furniture that is rented in these communities, do not address the prior issue of why there should be such demand for children's furniture. Choice C helps explain why these communities have an unusually high demand for rental furniture, but not why such a demand would extend to children's furniture.

CR Questions 1 - 10

1. Many institutions of higher education suffer declining enrollments during periods of economic slowdown. At two-year community colleges, however, enrollment figures boom during these periods when many people have less money and there is more competition for jobs.

Each of the following, if true, helps to explain the enrollment increases in two-year community colleges described above EXCEPT:

(A) During periods of economic slowdown, two-year community colleges are more likely than four-year colleges to prepare their students for the jobs that are still available.

(B) During periods of economic prosperity, graduates of two-year community colleges often continue their studies at four-year colleges.

(C) Tuition at most two-year community colleges is a fraction of that at four-year colleges.

(D) Two-year community colleges devote more resources than do other colleges to attracting those students especially affected by economic slowdowns.

(E) Students at two-year community colleges, but not those at most four-year colleges, can control the cost of their studies by choosing the number of courses they take each term.

Question 2-3 are based on the following

Hardin argued that grazing land held in common (that is, open to any user) would always be used less carefully than private grazing land. Each rancher would be tempted to overuse common land because the benefits would accrue to the individual, while the costs of reduced land quality that results from overuse would be spread among all users. But a study comparing 217 million acres of common grazing land with 433 million acres of private grazing land showed that the common land was in better condition.

2. The answer to which of the following questions would be most useful in evaluating the significance, in relation to Hardin’s claim, of the study described above?

(A) Did any of the ranchers whose land was studied use both common and private land?

(B) Did the ranchers whose land was studied tend to prefer using common land over using private land for grazing?

(C) Was the private land that was studied of comparable quality to the common land before either was used for grazing?

(D) Were the users of the common land that was studied at least as prosperous as the users of the private land?

(E) Were there any owners of herds who used only common land, and no private land, for grazing?

3. Which of the following, if true and known by the ranchers, would best help explain the results of the study?

(A) With private grazing land, both the costs and the benefits of overuse fall to the individual user.

(B) The cost in reduced land quality that is attributable to any individual user is less easily measured with common land than it is with private land.

(C) An individual who overuses common grazing land might be able to achieve higher returns than other users can, with the result that he or she would obtain a competitive advantage.

(D) If one user of common land overuses it even slightly, the other users are likely to do so even more, with the consequence that the costs to each user outweigh the benefits.

(E)There are more acres of grazing land held privately than there are held in common.

4. In tests for pironoma, a serious disease, a false positive result indicates that people have pironoma when, in fact, they do not; a false negative result indicates that people do not have pironoma when, in fact, they do. To detect pironoma most accurately, physicians should use the laboratory test that has the lowest proportion of false positive results.

Which of the following, if true, gives the most support to the recommendation above?

(A) The accepted treatment for pironoma does not have damaging side effects.

(B) The laboratory test that has the lowest proportion of false positive results causes the same minor side effects as do the other laboratory tests used to detect pironoma.

(C) In treating pironoma patients, it is essential to begin treatment as early as possible, since even a week of delay can result in loss of life.

(D) The proportion of inconclusive test results is equal for all laboratory tests used to detect pironoma.

(E) All laboratory tests to detect pironoma have the same proportion of false negative results.

Questions 5-6 are based on the following.

In many corporations, employees are being replaced by automated equipment in order to save money. However,many workers who lose their jobs to automation will need government assistance to survive, and the same corporations that are laying people off will eventually pay for that assistance through increased taxes and unemployment insurance payments.

5. The author is arguing that

(A) higher taxes and unemployment insurance payments will discourage corporations from automating

(B) replacing people through automation to reduce production costs will result in increases of other costs to corporations.

(C) many workers who lose their jobs to automation will have to be retrained for new jobs

(D) corporations that are laying people off will eventually rehire many of them

(E) corporations will not save money by automating because people will be needed to run the new machines

6.Which of the following, if true, most strengthens the author's argument?

(A) Many workers who have already lost their jobs to automation have been unable to find new jobs.

(B) Many corporations that have failed to automate have seen their profits decline.

(C) Taxes and unemployment insurance are paid also by corporations that are not automating.

(D) Most of the new jobs created by automation pay less than the jobs eliminated by automation did.

(E) The initial investment in machinery for automation is often greater than the short-term savings in labor costs.

7. The sustained massive use of pesticides in farming has two effects that are especially pernicious. First, it often kills off the pests' natural enemies in the area. Second, it often unintentionally gives rise to insecticide-resistant pests, since those insects that survive a particular insecticide will be the ones most resistant to it, and they are the ones left to breed.

From the passage above, it can be properly inferred that the effectiveness of the sustained massive use of pesticides can be extended by doing which of the following, assuming that each is a realistic possibility?

(A) Using only chemically stable insecticides

(B) Periodically switching the type of insecticide used

(C) Gradually increasing the quantities of pesticides used

(D) Leaving a few fields fallow every year

(E) Breeding higher-yielding varieties of crop plants

8. When a polygraph test is judged inconclusive, this is no reflection on the examinee. Rather, such a judgment means that the test has failed to show whether the examinee was truthful or untruthful. Nevertheless, employers will sometimes refuse to hire a job applicant because of an inconclusive polygraph test result.

Which of the following conclusions can most properly be drawn from the information above?

(A) Most examinees with inconclusive polygraph test results are in fact untruthful.

(B) Polygraph tests should not be used by employers in the consideration of job applicants.

(C) An inconclusive polygraph test result is sometimes unfairly held against the examinee.

(D) A polygraph test indicating that an examinee is untruthful can sometimes be mistaken.

(E) Some employers have refused to consider the results of polygraph tests when evaluating job applicants.

9. According to the new office smoking regulations, only employees who have enclosed office may smoke at their desks. Virtually all employees with enclosed offices are at the professional level, and virtually all secretarial employees lack enclosed offices. Therefore, secretaries who smoke should be offered enclosed offices.

Which of the following is an assumption that enables the conclusion above to be properly drawn?

(A) Employees at the professional level who do not smoke should keep their enclosed offices.

(B) Employees with enclosed offices should not smoke at their desks, even though the new regulations permit them to do so.

(C) Employees at the secretarial level should be allowed to smoke at their desks, even if they do not have enclosed offices.

(D) The smoking regulations should allow all employees who smoke an equal opportunity to do so, regardless of an employee’s job level.

(E) The smoking regulations should provide equal protection from any hazards associated with smoking to all employees who do not smoke.

10. Dental researchers recently discovered that tooth-brushes can become contaminated wth bacterial that cause pneumonia and strep throat. They found that contamination usually occurs after toothbrushes have been used for four weeks. For that reason, people should replace their toothbrushes at least once a month.

Which of the following, if true, would most weaken the conclusion above?
(A) The dental researchers could not discover why toothbrush contamination usually occurred only after toothbrushes had been used for four weeks.

(B) The dental researchers failed to investigate contamination of toothbrushes by viruses, yeasts, and other pathogenic microorganisms.

(C) The dental researchers found that among people who used toothbrushes contaminated with bacterial that cause pneumonia and strep throat, the incidence of these diseases was no higher than among people who used uncontaminated toothbrushes.

(D) The dental researchers found that people who rinsed their toothbrushes thoroughly in hot water after each use were as likely to have contaminated toothbrushes as were people who only rinsed their toothbrushes hurriedly in cold water after each use.

(E) The dental researchers found that, after six weeks of use, greater length of use of a toothbrush did not correlate with a higher number of bacterial being present.

Official answers and official explanations..

1. Choice B, the best answer, might explain the decreased enrollment at four-year colleges during the slowdown,but because it deals with graduates of two-year colleges it cannot explain why enrollment at these colleges might increase
Four of the choices give reasons why, in an economic showdown, many people would choose a two-year college.
Choice A indicates that a two-year college education gives one a better chance of finding a job when economic conditions are poor.

Choice C and E indicate why people with less money might prefer two-year colleges.
Choice D suggests that more is being done to attract people whose lives are affected by the slowdown to two-year than to four-year colleges.

2. Hardin’s claim is that common grazing land deteriorates more quickly than private grazing land because of overuse. The study indicates that common grazing land is currently in better shape, but this would not
undermine Hardin’s claim if common grazing land was in far better shape before grazing began. Thus, choice C is the best answer.
Choices A and E are inappropriate since the study can undermine Hardin’s Claim whether or not some ranchers use both sorts of land, or use only common land.

Similarly, the study can undermine Hardin’s claim whether or not ranchers prefer to use common land, as B says.
Finally, D is inappropriate since the force of the study is not
diminished if users of common land are more or less prosperous.

3. The study indicates that common lands are in better shape than private lands. The best answer, D, indicates that,
contrary to Hardin’s claim, it is in each rancher’s self-interest not to overuse common land, which would explain why common lands are in relatively good shape.
Choices A and C can only explain why private land is in better shape than common land, not the reverse.

Neither the fact that it is more difficult to attribute deterioration of common land to any particular user (choice B) nor the
fact that the relative amounts of common and private land differ (choice E) gives a reason for farmers not to graze their herds on common land as much as possible.

4. The most accurate test for pironoma would be the one with the fewest false results. If all tests have the same proportion of false negatives, then the most accurate is the one that has the lowest proportion of false positives. Thus, E supports the recommendation and is the best answer.
Choice A and C deal with the treatment for pironoma and are irrelevant to the accuracy of tests pironoma.
Choice B deals with the side effects of tests for pironoma, and does not address their accuracy.

That the proportion of inconclusive test results is equal for all tests (choice D) leaves open the question of which test is
more accurate, since it does not indicate which test has fewest false results.

5. The author argues that replacing employees with automated equipment might lend to less savings for corporations than anticipated, since laying off workers will lead to other costs. Choice B states the author’s main points and thus is the best answer.
The author argues that corporations that automate might incur unexpected costs, but the author does not argue that these costs will discourage corporations from automating (choice A).

The author does not address the issues of retraining (choice C) and rehiring (choice D).
Although the author argues that some unanticipated costs might offsets savings resulting from automation, the cost of running the new machines (choice E) is clearly not one of these unanticipated costs.

6. The threat envisioned by the author to the economic survival of workers displaced by automation will be serious only if they cannot find new jobs. Choice A, the best answer, says that there are already many such workers unable to find new jobs, and so strengthens the author’s argument.
Since the causes for declining profits for corporations that fail to automate are not analyzed in the passage, B is

By saying that costs associated with unemployment C weakens the argument.
Since the author
tacitly grants that, initially, automation will cut costs, the detail given in D provides us added support.

Choice E is
inappropriate because it concerns short-term rather than long-term results of automation.

7. Choice B gives a way of counteracting a serious drawback of the sustained massive use of pesticides. By periodically changing the pesticide used, pests resistant to one pesticide might be killed by the next pesticide, and those resistant to that pesticide might be killed by another, and so. Therefore, B is the best answer.
Choice A is inappropriate, since the effects of stable pesticides would simply be more persistent.

Gradually increasing pesticide amounts (choice C) will likely have no effect on pests already resistant to massive amounts.
Leaving a few fields fallow (choice D) is not relevant to the effectiveness of sustained use of pesticides.

Breeding higher-yielding crops (choice E) might temporarily increase yields, but not because of anything to do with pesticides.

8. The passage indicates that an inconclusive polygraph test tells nothing about the person who has taken the test, and yet employers sometimes refuse to hire someone whose results from such a test are inclusive. Treating lack of information as if it were unfavorable evidence about a person can reasonably be considered unfair. There, C is the best choice.
Choice A is not supported, since the passage says that an inconclusive polygraph test is no reflection on the examinee.

Neither B nor D is supported, since the information given includes nothing either implicit or explicit about polygraph tests that yield conclusive results.
Since the passage is consistent with both E and its denial, E is not supported.

9. The regulations allow some employees-those with enclosed offices-but not others the opportunity to smoke at their desks. If it is assumed that the regulations should allow all employees equal opportunity to smoke, those who are currently denied this opportunity should be given it, and so secretaries who smoke should be offered enclosed offices. Therefore, choice D is the best answer.
None of the other choices enables the conclusion to be properly drawn. Choice A tends to conflict with the conclusion, unless some enclosed offices are vacant.

Choice B supports no conclusion about how secretaries should be treated, Choice C undermines the conclusion.
Finally, nonsmokers already have equal protection from hazards, so choice E cannot be used to justify making any changes.

10. According to choice C, using a contaminated toothbrush does not increase the incidence of infection, so the recommendation to replace a toothbrush before it becomes contaminated is greatly undermined. Choice C is therefore the best answer.
Since the recommendation is based on the discovery that bacterial contamination occurs after about four weeks, the researchers’ inability to discover why contamination takes that long to appear does not weaken the recommendation (choice A), nor does their failure to investigate other forms of contamination (choice B), nor does the discovery that contamination does not worsen after six weeks (choice E). According to choice D, even thorough washing cannot prevent contamination, so replacing the toothbrush appears more essential, rather than less so.

Friday, September 29, 2006

Critical Reasoning - Approach


Logistics of the Arguments Section

The arguments comprise one-third of the Verbal section of the GMAT i.e approximately 14 questions.

What is an Argument ?

An argument is an attempt to provide a reason for believing something by citing something else.No of claims are put forward in an argument,the claim that is being supported is the conclusion.Claims alleged to support the conclusion are the premises.

Words ,Phrases supporting Conclusions:

This shows that;
We can infer that;
It follows that;
This indicates that;
For that reason,we may say;

Words ,Phrases introducing Premises:

The reason is that;
On the basis of;
t follows from;
In view of;
We may infer from;

Gap between Premises and Conclusions is Assumptions—identify the gaps and use it to find the solution.

Classification of Arguments

Deductive arguments are those in which the conclusion necessarily follows from the premises/evidence. It shows tight connection between the Premises and Conclusions. Most arguments on the test are inductive, where the author presents the evidence as support for the conclusion. The validity of the conclusion depends on the strength of the evidence.

Unlike deductive arguments, the conclusion of an inductive argument is always uncertain. You must be prepared to handle both reasonable arguments (when the conclusion is likely) and false arguments (when the conclusion is improbable). Each classification of inductive reasoning carries its own associated fallacies.

Evaluation of an Argument—To find errors in Arguments

(1) If-Then Statements

Most arguments are based on some variation of an if-then statement, which may be either directly stated or embedded. Understanding the if-then premise reveals the underlying simplicity of arguments.

If the premise of an if-then statement is true, then the conclusion must be true as well.

If A, then B

While three possible statements can be derived from the implication "if A, then B", only one is valid.

The statement that IS logically equivalent to "if A, then B" is called the contrapositive. It is stated as:

If not B, then not A

Let's explore why this is true.

"If there is a hurricane, then Samantha will cry"

There are four different hypothetical possibilities to consider when making deductions based on this statement:

1) A hurricane occurs
2) A hurricane does not occur
3) Samantha cries
4) Samantha does not cry

Let's consider each individually:

1. If a hurricane occurs.

You know that if this is true, the result will be that Samantha will cry.

2. If a hurricane does not occur.

If a hurricane does not occur, you can deduce nothing about Samantha. In particular, you cannot deduce that she does not cry. There are many other reasons why Samantha could cry, besides a hurricane (fight with her mom, she sees a sad movie, she gets sick).

3. If Samantha cries.

Again, you can't deduce anything about the occurence of a hurricane if Samantha cries. The if-then statement doesn't assert that Samantha cries only if a hurricane occurs, just that if it does, Samantha will cry. Samantha can cry even on clear, sunny days.

4. If Samantha does not cry.

If Samantha does not cry, you can deduce that a hurricane did not occur. Why? If it had occurred, then Samantha would definitely have cried. Yet she didn't. So, we know that, given Samantha's disposition, a hurricane did not occur.

To review, any time you see a statement in the form of "If A, then B", contrapose the statement into "If not B, then not A".

You know only two things:

a) what will happen if X occurs
b) what will happen if Y does not occur.

Those are the only valid deductions that you can make based on that original statement.

You can only assume two things about the implication "if A, then B":

1) If A is true, then B must be true.
2) If B is false, then A must be false.

2) Embedded If-Then Statements

If-then statements are frequently embedded in other structures, making their detection more difficult.

Example: (Embedded If-then)

Jamie and Kyle cannot both go to the mall.

At first glance, this sentence does not appear to contain an if-then statement. But it essentially says:

"if Jamie goes to the mall, then Kyle does not."

The contrapositive ("if Kyle goes to the mall, then Jamie does not") correctly expresses the same thing.

Example: (Embedded If-then)

Heather will go to Europe only if she gets a raise at work.

Given this statement, we know that if Heather goes to Europe, she must have gotten a raise at work.Students often wrongly interpret this statement to mean:

"If Heather gets a raise at work, then she will go to Europe."

We have no guarantee of this. The only guarantee is that if Heather doesn't get the raise, she will not go to Europe.

"A only if B" is logically equivalent to "if A, then B"

Fallacies from no.3 to no.15 are not important for Critical reasoning Questions but a student should know about them

3) Circular Reasoning

Here an unsubstantiated assertion is used to justify another unsubstantiated assertion,which is,or atleast could be ,used to justify the first statement.For instance,

Full scholarships are appropriate for disadantaged scholars because it is right to offer a top-notch education to those most capable.

This argument is circular because "right" means essentially the same thing as "appropriate." In effect, the author writer is saying that scholarships are appropriate because they are appropriate.

(4) The Biased Sample Fallacy

This is commited whenever the data for a statistical inference is drawn from a sample that is not representative of the population under consideration.

For example:

In a recent survey conducted by The Times of India of its readers,60% of the respondents indicated strong support to Lalu Prasad Yadav.Hence the survey clearly shows that Lalu yadav is the most popular leader among the masses.

The data for the inference in this argument is drawn from a sample that is not reprentative of the entire electorate.

6) The Insufficient Sample Fallacy

The Fallacy of the Insufficient Sample is committed whenever an inadequate sample is used to justify the conclusion drawn.
Here's an argument that commits the fallacy of the insufficient sample:

I have worked with three people from Bangalore City and found them to be obnoxious, pushy and rude. It is obvious that people from Bangalore City have a bad attitude.

The data for the inference in this argument is insufficient to support the conclusion. Three observations of people are not sufficient to support a conclusion for whole city population..

(4) Ad hominem

One of the most often employed fallacies, ad hominen means "to the man" and indicates an attack that is made upon a person rather than upon the statements that person has made.

An example is "Don't listen to my opponent; he's handicapped."

(7) The Fallacy of Faulty Analogy

Reasoning by analogy functions by comparing two similar things. Because they are alike in various ways, the fallacy is that it is likely they will share another trait as well. Faulty Analogy arguments draw similarities between the things compared that are not relevant to the characteristic being inferred in the conclusion.

Here's an example of a Faulty Analogy fallacy:

Ram and Shyam excel at both football and basketball. Since Ram is also a singer, it is likely that Shyam also excels at singing.

In this example, numerous similarities between Ram and Shyam are taken as the basis for the inference that they share additional traits.

(8) Straw Man

Here the speaker attributes an argument to an opponent that does not represent the opponent's true position.

For instance, a political candidate might charge that his opponent "wants to let all prisoners go free," when in fact his opponent simply favors a highly limited furlough system. The person is portrayed as someone that he is not.

(9) The "After This, Therefore, Because of This" Fallacy (Post hoc ergo propter hoc)

This is a "false cause" fallacy in which something is associated with something else because of mere proximity of time. One often encounters people assuming that because one thing happened after another, the first caused it, as with "I stood up; Sachin got out. My standing up resulted in a loss of wicket." The error in arguments that commit this fallacy is that their conclusions are causal claims that are not sufficiently substantiated by the evidence.

Here are two examples of the After This, Therefore Because of This Fallacy:

Ten minutes after walking into the auditorium, I began to feel sick to my stomach. There must have been something in the air in that building that caused my nausea.

In the first example, a causal connection is posited between two events simply on the basis of one occurring before the other. Without further evidence to support it, the causal claim based on the correlation is premature.

(10) The Either or Thinking

This is the so-called black or white fallacy. Essentially, it says "Either you believe what I'm saying, or you must believe exactly the opposite."

Here is an example of the black or white fallacy:

Since you don't believe that the earth is teetering on the edge of destruction, you must believe that pollution and other adverse effects that man has on the environment are of no concern whatsoever.

The argument above assumes that there are only two possible alternatives open to us. There is no room for a middle ground.

(11) The "All Things are Equal" Fallacy

This fallacy is committed when it is assumed, without justification, that background conditions have remained the same at different times/locations. In most instances, this is an unwarranted assumption for the simple reason that things rarely remain the same over extended periods of time, and things rarely remain the same from place to place.

The last time winner of south delhi constituency won the general election. This year, the winner of the south delhi constituency will win the general election.

The assumption operative in this argument is that nothing has changed since the last primary. No evidence or justification is offered for this assumption.

(12) The Fallacy of Equivocation

The Fallacy of Equivocation occurs when a word or phrase that has more than one meaning is employed in different meanings throughout the argument.

"Every society is, of course, repressive to some extent - as Sigmund Freud pointed out, repression is the price we pay for civilization."

In this example, the word repression is used in two completely different contexts. "Repression" in Freud's mind meant restricting sexual and psychological desires. "Repression" in the second context does not mean repression of individual desires, but government restriction of individual liberties, such as that in a totalitarian state.

(13) Non Sequitor

This means "does not follow," which is short for the conclusion does not follow from the premise. To say, "The house is white; therefore, it must be big" is an example of the Non Sequitor fallacy. It may be a big house, but there is no intrinsic connection with its being white.

(14) Argument ad populum

A group of children are playing, trying to determine no of balls in an opaque box. "I wonder if there are less than 4 or more than 4 balls in the box," says one student. "I know how we can tell!" pipes up another. "All right, how?" asks the teacher, resigned to the worst. Beams the child: "We can vote."

This is argumentum ad populum, the belief that truth can be determined by more or less putting it to a vote. Democracy is a very nice thing, but it doesn't determine truth. Polls are good for telling you what people think, not whether those thoughts are correct.

(15) Contradiction

Contradiction occurs when a writer asserts two opposing statements simultaneously. For example, saying "it is wet and it is dry" is a contradiction. Typical arguments on the test obscure the contradiction to the point that the argument can be quite compelling. Here's a great example:

We cannot know anyone, because we intuitively realize that people are unreliable.

At first glance this argument sounds reasonable, but "intuitively realize" means "to know." Thus the author is actually saying that we know that we don't know anyone. This is classic contradiction.

Typical Questions

Despite the wide variety of arguments used on the test, there are essentially only eight types of questions that are asked.

1) Assumption Questions

When a question asks you to find an author's assumption, it's asking you to find the statement without which the argument falls apart.Make use of denial technique. Simply negate the statement and see if the argument falls apart. If it does, that choice is the correct assumption. If, on the other hand, the argument is unaffected, the choice is wrong.

Below are stated some of the ways in which assumption questions are worded:

Which one of the following is assumed by the author?
Upon which one of the following assumptions does the author rely?
The argument depends on the assumption that. ..
Which one of the following, if added to the passage, will make the conclusion logical?
The validity of the argument depends on which one of the following?
The argument presupposes which one of the following?

2) Strengthen and Weaken Questions

An argument can be weakened by destroying a central piece of evidence or by attacking the validity of the author's assumptions. In contrast, an argument can be strengthened by providing additional support, by affirming the truth of an assumption or by presenting additional persuasive evidence.

Here are some of the ways in which strengthen/weaken the argument questions are worded:

Which one of the following, if true, would most weaken the argument?
Which one of the following, if true, would most strengthen the argument?
Which one of the following, if true, would most seriously damage the argument above?
Which one of the following, if true, casts the most doubt on the argument above?
Which one of the following, if true, is the most serious criticism of the argument above?
Which one of the following, if true, would provide the most support for the conclusion in the argument above?
The argument above would be more persuasive if which one of the following were found to be true?

3) Inference Questions

Inference questions require you to consider the statements as evidence and then draw a conclusion from them. A valid inference is something that must be true if the statements in the passage are true. It is an extension of the argument rather than a necessary part of it.

Inference questions probably have the most varied wording of all the Logical Reasoning question stems. Some are obvious, others are subtle, and still others may resemble other question types.

Below is the quick rundown of the various forms that inference questions are likely to take on your test:

Which one of the following can be inferred from the argument above?
The author suggests that. ..
If all the statements above are true, which one of the following must also be true?
The author of the passage would most likely agree with which one of the following?
The passage provides the most support for which one of the following?Which one of the following is probably the conclusion toward which the author is moving?

4) Flaw Questions

This question asks you to recognize what's wrong with an argument. Most critique the reasoning by pointing out a fallacy. Other flaw questions are more specific and attack the argument's reasoning.

Here are typical flaw questions:

Which one of the following contains a flaw that most closely parallels the flaw contained in the passage?
The speakers will not be able to settle their argument unless they
The conclusion above is unsound because
Which one of the following best identifies the flaw in the above argument?
In presenting her position the author does which one of the following?

5) Method of Argument Questions

Method-of-argument questions ask you to pick the choice that describes how the authorpresents her case. To tackle these, you must be able to analyze the structure of an argument. If you can't identify the evidence and conclusion, you'll have difficulty describing how an argument works.

Most questions involve classic argumentative structures, such as "arguing from a small sample to a larger group," or "inferring a causal relationship from a correlation." The other type of method-of-argument question gives a description of the argument in much more specific terms. Anexample of this might read, "The author presents his case in order to show that......"

6) Similar-Reasoning Questions

Similar-reasoning questions require you to identify the answer that contains the reasoning most similar to that in the stimulus. The key is to summarize the argument's overall form and match it to that of the correct choice. A good approach to these questions is to see if the argument can be symbolized algebraically, using Xs and Ys.

Example: All fish swim. This creature swims. Therefore, it must be a fish.

This (flawed) argument can be symbolized in the following way:

All X do Y. This does Y. Therefore, this must be an X.

If the stimulus can be symbolized this way, your job will be to search for the choice that can be symbolized in the same way. Your answer might look something like this:

Every mother (all X) loves singing (does Y). Jenny is singing (this does Y). So she must be a mother. (therefore, this must be an X).

7) Paradox Questions

When an argument contains two or more seemingly inconsistent statements, it presents a paradox. Most paradoxical arguments end with a contradiction. Another type of paradox has the argument build to a certain point, then change to the exact opposite of what you expect.

In a typical paradox question, you'll be asked either to find the choice that "explains the paradoxical result", "explains the inconsistent findings", or "resolves the apparent discrepancy." This will be the choice that reconciles the seemingly inconsistent statements in the argument while allowing them all to still be true.

8) Principle Questions

Principle questions ask you to apply a specific situation into a global generality (or vice versa). You may be given an argument and asked to find the principle that justifies the author's reasoning.

Possible question stems:

The author's position most closely conforms to which one of the following principles?
What principle best accounts for or justifies the author's position?
Which one of the following principles would justify Al's refusal to follow the author's recommendation

The correct answer to principle questions expresses the key concepts and contains the key terms that the other choices omit. Avoid choices that are beyond the scope of the argument. Most of the wrong choices contain principles that sound formal and look reasonable, but they don't address the author's main concern.